For a glider vet fund it is a good idea to have $500-$1000(more if you can, the hope is that you will never need it)set aside in case of emergencies. (I just spent over $500 on treating a bite wound last week).
There is always "Care credit" that most vet accept now too.
What a Vet charges will very much depend on where you live and how many vets see exotic pets and sugar gliders in your area...not all exotic vets are even familiar with them.
Some have paid as little as $45 for a vet check and fecal test to over $150, so you will have to call around a get pricing from them.
Two gliders will actually bond quicker than having just one and then you don't have to deal with the whole 30 day quarantine and then the scent swapping to get your gliders used to each others scent and then the face to face introductions. Which can take up to 45 days.
If you are interested in breeding it is recommended that you own gliders for at least a year and work with a breeder(mentor)so you really know what you are delving into. If you choose to breed, gliders need to have "Lineage"(and breeding rights). That is the only way you will know for sure gliders are not closely related. There is a lot that can go wrong in breeding and a lot of expense in keeping extra cages and neutering males and such...
Older gliders are not any harder to bond with than getting joeys from the start unless they literally have never been handled.
With my Newest gliders I got last summer the male(former breeder and parent to 4 of my joeys)is the sweetest boy in the world and bonded to me immediately, he is more bonded to me than my first pair of his twins)
Then they can take more time an patience but each glider has it's own unique personality and some will take longer than others just due to that fact alone. His mate(the Momma) is not what I would consider bonded to me at all. She likes me fine(I think), but she is not the cuddly sort.
If you get two males, they should both be neutered to prevent any territory arguments. 2 girls or a girl and a neutered boy is fine too. My first pair are twin brother and sister and I had brother neutered at 12 weeks so he couldn't mate with his sister.
There are many gliders in need of homes(Check the "My glider needs a home" page...many people fall in love with these guys and then their life situations change and they can't keep them. So that's a great place to start.
For the PVC cages, some gliders are chewers but I have not heard of anyone having a problem with them chewing the land ware mesh. That is really the only safe material to use...anything metal is galvanized and it reacts chemically with the glider pee and the zinc is toxic. Even manufactured cages can be unsafe for gliders. Powder coating is what is approved and you have to make sure to check often to make sure there is not any rust.
here is the tutorial link:
http://www.justforfuzzies.com/Other_Stuff/Cage/index.html