New! Please help!

Plastic is a little tricky when you consider the high heat. I generally stay away from plastic items. The high heat bearded dragons require can make certain kinds of plastic melt or potentially emit questionable chemical fumes. There are companies (like Animal Plastics) that do make cages and decor from high grade pet safe plastic that doesn’t melt or emit chemical fumes over time, but with everyday plastic items I’d take a pass to be on the safe side. The object you’re talking about wasn’t designed to stand up to high heat/UV light so that could be problematic. Sidenote: Your friend doesn’t give his beardie adequate UV light, feeds it nothing but mealworms, has no idea whether his beardie is freezing or dangerously hot on a daily basis but he’s concerned about a plastic object being unsafe? That’s kind of like letting your kids play in toxic sewage all day but making sure they wear their seatbelt on the ride home.

Like I said, he's literally crazy. But I'll let him know about the plastic.

I’d definitely encourage a “better safe than sorry” approach and get him to ditch it. His judgment concerning animal health has been pretty horrifying thus far so hopefully he won’t add anything new to the mix. His poor beardie is already likely fighting a huge battle to thermoregulate, survive without adequate UV light, and pass all those mealworms. Hope you’re able to have a positive influence over the situation. And hope Marbles is doing well and gearing up for a big growth spurt.

Marbles seems to be doing really well. He finished shedding today I think, but he doesn't seem too into small crickets anymore (we had to switch to mediums for a while because the store was out of smalls). Should I keep trying with smalls or go back to mediums? Also how bad for him is it when he eats a dead one before I can get it up?

If he managed to snatch a dead cricket before you could stop him don’t panic. One dead cricket likely won’t have a dramatic consequence, but you definitely don’t want to make a habit of it. Dead insects can quickly accumulate bacteria and eventually parasites, but as long as it was just a one-time occurrence chances are he’ll be fine.
As beardies grow, it’s not uncommon for them to snub the tinier crickets that were proportional to them when they were babies. If I were to try and feed some of my adult beardies the small size crickets, they’d just stare at me as if to say “these aren’t worth my time.” So as your beardie grows, so can the size of his crickets. I forget how old your little guy is, but as long as the medium sized crickets aren’t longer than the space between his eyes than they’ll be fine (and it’s more economical too).
Any pics of the growing boy and his new digs?

The small crickets are more proportional for him, but he will hardley eat them now. I think he's filling up on his salad first maybe? He REALLY likes mustard greens apparently. I'll get a picture tonight

So this is how he was when I got home today haha

Aww, such a cute little guy! Looks like he’s got a nice assortment of climbs, caves, and perched too. It’s great that he likes his salads (many babies are notorious for snubbing them). One thing you can try to make sure he gets adequate daily protein is to offer salad midday (after bugs). Then hopefully he’ll wolf down a good amount of insects before diving into his salad. Additionally, feeding him a few hours after his lights have been on and his metabolism and body temperature are revved up can help stoke his appetite. A baby beardie that loves his greens is a blessing. As long as he’s still got an appetite for bugs it just means he’ll have a nicely varied diet. Sometimes beardies get bored with certain foods, so introducing BSFL or small dubias may help reignite his interest in bugs.

Unfortunately, the only feeders available around here are crickets and mealworm. Oh, and I actually chewed out the pet store today for mistreating their beardies. I go there every week for crickets, and now they've got an adult. He has no shelter, tiny water bowl, no baths, a tiny amount of kale and crickets, and they don't even know what temperature his basking spot is! If they don't fix it, I am definitely calling someone to have the place shut down for animal cruelty. You should see the fish tanks.. it's just nasty

That’s so awful that a pet store sees nothing wrong with neglecting the animals they’re supposed to be an authority on proper guidance for. You definitely get a hero badge if you stood up for that poor little beardie. And if the fish tanks are gross then the neglect of their beardies isn’t a fluke, and my guess is that very few of the animals in that place are being cared for properly. While beardies have become popular as pets, they’re still exotic animals that have vitally specific environment and dietary requirements. A hamster may be able to digest its food at room temperature, but if these jerks don’t care whether their reptiles are in a world of pain because they can’t thermoregulate and have normal bodily functions then they don’t deserve to be in business. Good for you for letting them know that neglecting their animals isn’t okay. If you feel like they could care less whether people have noticed the poor conditions then you can always report them (at which point they’ll either be forced to provide adequate care or shut down if the violations are deemed too numerous and egregious). I once took some photos of some horrifically neglected baby beardies at Petco and showed the numerous violations (inadequate heat, severe overcrowding, emaciated lizards, etc.) to the manager. All it took was the fear that I might post the photos on Yelp and he quickly addressed the issues. But this wouldn’t be the last time I encountered pet stores that had no business selling reptiles. When I volunteered at an animal shelter, I was horrified by the number of reptiles that had been rescued from the brink of death from pet shops. It convinced me that adoption or verified/respected breeders would be the only way I’d acquire bearded dragons for the rest of my life. You’ve become quite the lizard crusader. Sounds like you’ve been a good voice for some neglected lizards lately.
I’ve found that most pet stores have a limited assortment of insects, so if you need some references for buying insects online let me know. The pet stores charge pretty outrageous prices for crickets. I just ordered 200 crickets for about $4 from Rainbow Mealworms and I don’t think $4 would buy more than two dozen crickets at Petco (if that). And red runner roaches and BSFL are another economical option if you order online. I currently have several beardies and I pay less than $40 a month by ordering all their insects online (roaches, BSFL, hornworms, crickets, and occasional superworms or butter worms as treats).
Marbles was looking very happy and healthy in that photo. Has he had a little growth spurt lately? It’s crazy how much they can grow in such a short period. I miss having a baby. Luckily one of my adults has the persona of a puppy and that helps me fight the urge to bring home a new baby every time I’m at a reptile expo.

I think he's doing pretty good. My issue with feeders though is keeping them alive, I'm scared if I got 200, they'd all be dead before he got around to actually eating them all. I'm also scared they'd be dead before I even got them out the mailbox

When ordering insects online you can check “hold at post office” if you’re worried about temps in your mailbox or on your porch. Crickets do have a higher die off rate than some of the other feeders (not a super long life span) but as long as you don’t order the largest size they’ll last a while. I tend to order a large amount of mediums so they have room to grow and I don’t have to worry about them dying before I can feed them all off. Dubia and Turkistan roaches are fantastic because they have a much longer life cycle and are much hardier/easy to keep thriving. And BSFL require zero food or maintenance, and if the worms do pupate before you can feed them all off then you can feed the flies to your beardie when they hatch. One of mine lives for chasing black soldier flies. It’s like watching a hungry parkour expert. I know money was a bit tight, so that’s why I mentioned the online insects. It’s a great way to ensure diet diversity and has saved me a ton of money over the years, but if the prices where you buy your feeders are reasonable then you don’t need to bother with it. Keeping a large amount of insects on hand takes some getting used to and it’s not for everyone. As long as your baby is getting a steady supply of bugs then you don’t need to become an insect farmer.

I was interested because you said you got 200 for 4$. I can get maybe 60 for 6$

That’s better than a lot of the chain stores as far as pet store prices go, but if you order with Rainbow Mealworms or Fluker’s you can also throw BSFL and other bugs into the order. Getting a variety pack every month has made feeding my beardies a variety of insects so easy, but the trade off is that keeping all those bugs alive and healthy can make you feel like you’ve got a second pet. So there’s definitely a downside.

In that case, I don't think I'm ready for that step