Crested or gargoyle geckos all the way. No additional heating is required, there are inexpensive colors/patterns all the up to costly high end specimens, no insects needed (unless you choose to do so), cheap and small housing, easy to feed and cheap to buy diet, docile, the list goes on.
I'd highly recommend this species over anything else. I've had tons of different reptiles and these are by far one of the least expensive, rewarding, and hardiest reptiles around. Here some pictures of my little ones.
Cheap hatchling setup for under $5 total
Medium cost R-Zilla acrylic atrium $40-50 for the cage alone(my personal favorite)
or, a more costly exo-terra $90-125 new for the cage itself
Well, if that doesn't convince you...