Why don't you try a Kenyan Sand Boa? They don't get big at all (something like 2 feet) and aren't too heard to take care of. They don't need a huge enclosure either
I know that they are readily available and not too expensive unless you want to get into some of the 'morphs' that are available.
If you'd like something bigger but still not too big, a ball python or childrens/spotted python might be a good choice.
Just do some research and look for something thats for you