The Federal GOvernment has a department of Endangered Species(there's a program for indigos, right? Just add more species).

Also, you can find Galapogos tortoises for sale IF you have a permit to own them. Captive breedings have all but ensured that almost ALL of the species(subspecies) of Galapagos Tortoise will not be extinct. If you are offering only captive bred specimans, then it should result in MORE animals overall, rather than decreasing the number of animals.

Plus, remember that of all animals, reptiles have the tendancy to have large clutches of eggs at a time, rather than many mammals that might have only one or two young at a time. Reptiles should be easier to save from extinction by far, given proper husbandry over the species.