What species are you considering? And what are you planning to feed them? Many species can be fed a varied diet, so feeding price will vary based on your choices.
Initial setup for a reptile is always the most expensive. I like Garters housed in tanks because they are diurnal and enjoy basking. They are also very curious and will come up to the glass to see if you're bringing them food. A 20gal tank is min for one adult Garter. I like to give them overhead heat and light. I use Aspen for substrate because they burrow easily into it. Like Kcl said, they have a varied diet. I feed some of mine tilapia with calcium. Others I feed pinkies. Garters can also be house communally which is nice if you have more than one.