I am not sure if this is really a good idea. Here in Austria, "regular" corn snakes can only be sold as hatchlings, nobody wants adults. And the price if you are not in a shop ranges from 10 to 30€ per animal. This can't pay for itself, because in Glasgow outside keeping for saving costs is impossible. Same goes for leopard geckos.
Try breeding something a little more rare and still easy to keep like Nephrurus or Rhacodactylus (although ciliatus is probably not rare). If you want to invest a little more into lighting, breeding small Phelsumas and Lygodactylus (especially williamsi) is rewarding. For L. Williamsi you missed a good time to start, but it might not be too late. They just discovered thaht the species is endangered and soon imports will stop (maybe they already have), so the price wont drop but rather rise.
Regardless of the species I would recommend a breeding stock of 2.2 to 2.4 for each color morph or species with the males being kept separately, which makes up to 6 tanks depending on species. That way you can control which male mated which female. Then you need lots and lots of tanks to raise babies and a huge incubator. Finally one last advice: don't buy animals with doubtful origin, only buy your breeding stock at serious breeders and collect a lot of literature: keeping, breeding & incubation, health care.
