Okay first even though you feel sorry for them and all it is not a very good idea to get igs from a pet store for several reasons. If they do not look to be in very good health they can run up lots of vet bills before you even start with the costs for enclosures etc. Second buying from a pet store just allows them to buy more to put in the same poor care. Also if thinking of getting more than one you cannot house them together. I realize pet stores do but this is for them to keep costs down not because it is healthy for them!!
If you have read up on them you will know that healthy iguanas can grow very fast. A 30gallon is not a good idea as they would quickly need something larger (each of them). It is best to build the largest enclosure possible to begin with as they will very soon need a 6'x6'x4' or larger cage. I realize this sounds big when you look at a baby ig but believe me its not.
Please get Melissa Kaplan's Iguanas for Dummies or else James Hatfields book Green Iguana Ultimate Owners Manual. Please read one or both before buying or adopting and they should answer all your questions.
If you have never had an iguana before which I'm assuming you haven't please start with only one and only after you have done a lot more research.
We run a rescue and I see constantly iguanas from homes where they have gotten "too big" "too aggressive" "too messy" "too costly" and just "too everything" Even had one said it was "too noisy" How can this be when they don't make noises like say a dog?!!!
If you really want an iguana after researching it then good luck but still think twice about the pet store unless the iguanas are in very good condition and being cared for correctly which can be rare in business.
also for more info try Kaplan's site I think it is www.anapsid.com but I'm not sure you should be able to find it on a web search.
Stephanie