Jamiedog is right, DO ask for discounts. I've done a ton of rescue work, and there are vets who will give discounted services for rescues.
One thing you're going to have to realize, is you can't save them all. Extreme neglect in reptiles has been a HUGE problem forever. In the neglect department reptiles actually take the number one spot. They are considered (by the majority) to be throw away pets who don't have feelings. Just look how many times in movies and tv a pet turtle has been lost in a garbage disposal. And the usual response is Oops! lol, or darn it, now I have to find another turtle and hope the kids don't notice. Get what you can, and give them the what you can, and try not to think about the rest. If you can't afford to take in another animal, don't even look. You'll just torture yourself, or guilt-trip yourself into and spread yourself too thin.
DO NOT spend too much to get a rescue. I personally won't spend much buying the animal at all. I've gone with donations only and still had a house full of animals, and had to turn some away. The more money you spend acquiring an rescue the less you have for their care of all your animals.
DO NOT go all out on their vivs. Give them a small basic no frills set-up to start. If they're sick, they're not going to be that active, and you'll have to keep their vivs meticulously clean anyways. Most rescues live in too small tanks anyways, it doesn't take much for an improvement from their perspective. Once they get better, you can upgrade them to a nicer one. I rescued a large iguana who never even had a viv in my home. I couldn't afford it, but she was in too bad shape to turn away. So I sectioned off and iguana proofed my kitchen and hung some lights from my table. It wasn't pretty, but it worked.
Get a network of rescuers. There are a lot of like-minded people, and probably several in your area. Join your state's herpetology society, meet people at shows, or other animal shelters, your vet might know some people. Occasionally you'll find a pet store employee who got the job to save the animals. If it's something you can't do, pass it down the network. Don't be afraid to say you have a rescue you can't handle. IMO there's no shame in admiring you can't provide what is needed, and giving it to someone who can. With the iguana I mentioned above. I couldn't afford her long term.. But i could give her a uv, heat, proper diet and a vet check. Which was a billion times better from what she had before. So I took her until I could find her better. It was far from perfect, but I made a HUGE difference in her life.
If possible try and find a few shelters or facilities that can take the occasional long-term occupant. It's only a matter of time before you run into an animal that has become an unsuitable pet for the average owner. It could be disabilities, expensive and/or time consuming long term health issues, or severe aggression or behavioral problems. Special needs animals are very very difficult to place. In some cases, a long term shelter, sanctuary or zoo like place might be the best option for them.
Also, I recommend getting a subscription to a reptile care magazine, and getting links to various reptiles and reading up on them. Once people find out you rescue reptiles, you'll get lots of offers of animals in dire need. Some are hard, and some are a cinch to care for. There are a lot of different reptiles you could feed with stuff you are already buying for your bd. Some might not necessarily cost you much if any to feed. In some circumstances herbivores might even make you more cost efficient. They can help finish off produce before it goes bad, and encourage you to buy more variety to make all your salads better for all your animals.
I'm not saying you have to, or should take in other reptiles. But as an animal/reptile lover and rescuer it can be hard to walk away. there are many reptiles that share a lot of needs with bds, and with a little basic knowledge then you don't have to turn them away if you don't want to. You don't have to become an expert, but a general knowledge of reptiles can go a very long way. If you can provide better than what they had for a short term, long enough to find someone with more experience, you will make a difference. Even if you can only give heat and food for long enough to place them with someone more experience or better equipped, it CAN save a life. even if they need a billion other things to be healthy, a proper diet can give them the strength they need to tackle everything else.
That's all I can think of right now.
I felt she would be better off in the same cage at least with the right heat and light and the right diet. She has improved immensely since. 
