I've .. a few .. and love them - when they're done well. DON'T pick a picture of the tattooist wall and hang it on your skin - you'll regret it without fail! I always recommend you use your skin as a canvas that is also part of the scene (hope that makes sense) and not just for tramp stamps (don't get me wrong i speak from experience). Don't choose the nearest tattoo shop, choose an established place of some time, then start to run some ideas past the tattooist. If you have a style you like, say something like demons, there will be one of the tattooist in there who specializes in that design or like tattooing that style. Get to know your tattooist and discuss things with them, they have some great ideas if you give them free reign. If you want some bigger work you'll be able to get a 'day rate' to cut down on costs.
HTH