I have my
uvb light in the under cabinet fixture from walmart, the light was $30 and the fixture was $7, I bought professional strength velcro and stuck it just inside the tank so that he can vget within inches from it on his basking spot. I have him in a 50 gallon tank I got on freecycle.org and built a platform box with a ramp for him to get up to his basking spot. I got fake tile from the dollar store and have that on the bottom.
There are people who say sand is okay but I think there are more risks than are worth it. I don't like sand becuase of the impaction risk, problems with the eyes, it can start stinking...my beardie when he poops also has liquid that is there (apparently normal with well
hydrated beardies) and even though you can scoop I can't imagine you get it all out and it would smell. When we got him he had been on sand and although he was clean and well taken care of he still smelled like the sand and there was a smell that I didn't like. So I don't want to be dealing with the sand even if it were safe for them. Just my opinion.
As far as the
UVB light reptisun is truelly the best you will see the biggest difference under that light. You still need basking and heat lights though...depending on your set up can probably use different wattages of lightbulbs. It didn't work for our set up but others have been successful so it doesn't hurt to try. Walmart has a great thermometer with the probe that is like $12 and is perfect!
Even though it sounds like he had a bumpy start you are at least doing your research now and hopefully it will be fine. We all make mistakes when we get our pets, we are human! Heck I thought I had the right light for mine and it turned out I didn't! So he went a month without uvb apparently. Hang in there and as long as you do whats best now you will probably have lots of luck!