If this is your first reptile, then I would recommend a leopard gecko. I have one and they are the one of the easiest reptiles to take care of and they're really friendly. Unlike other reptiles, they do not need a heat lamp or heat pad because there normal temperature that they survive in is about 73F. But some are a bit unfriendly and dislike being handled.
They basically only need a water bowl, a hideout, of course a tank (about 10-30 gallons), either sand and you would need to feed him or her 3-4 crickets a day. And crickets are really cheap so you can just go to your local pet store and buy 15-30 crickets every week or so. But take my word, these are the EASIEST reptiles you could ever have. (and they are EXTREMELY friendly and full of personality)
If you already have a leopard gecko than try getting a bearded dragon. Now these DO require a heat lamp and a basking spot (a large, sanitized rock would work) and they are more expensive then leopard geckos. These, as I said for the leopard geckos, are very very very friendly and full of personality. :]
Bearded dragons are better by far and have much more of a personalty and all so are much more attaching if you know what i mean. If i were you i would get a bearded dragon. If you struggle keeping it get a leopard gecko.