Tattoos can be a great experience, or an awful one. Think long and hard about if you want one, and try to pick something with a personal meaning. Make sure it can be covered up, aviation is really conservative and they seem to really dislike tattoos (and beards, such a shame mine will have to go when I get to the airlines *sniffle*). As far as costs go it is usually based on time and complexity, and with tattoos you get what you pay for.