I'm getting a tattoo some day
A unicorn on your left butt cheek?
In anyway to give you some insight, since it is your first tattoo. Be warned, once you get one, you will want more, I got 3 (all relatively small) and working on a fourth (a half sleeve on my right hand). All black and white. It is an awesome feeling and as long as you get something meaningful it is something that you will never regret.
Now, for pricing. May people do it differently. Some parlors will charge only for the hour, usually between 100-200$/hr depending on the artist's reputation. Some more well known people will charge more, but that doesn't seem to be your problem. If the artist gets involved, or it looks like a big piece, it might be they charge you per piece, as their estimate of how long it would take. Some places do the reverse (like under 2-3 hours of work they'll give you a set amount where for large pieces they will go per hour). I would say, get creative with your idea, put a unique spin on it, sit down and talk to the artist, because if you get them involved and inspired they might want the piece to become a part of their portfolio and will even offer you a good discount (I am talking to my new artist currently and he wants to do my piece soo bad he's giving me like 20-30% off so we can get it done).
As for the pain, it depends on the area. Usually the places close to the bone or sensitive areas are bad. I don't have one in any of those yet so I can't comment, but expect ribs, elbows, chest, knee, inside the elbow and inside the knee. All of those will definitely hurt, back too. Everything else, more than bearable.
Also, don't make the same mistake I did and go get your first tattoo on an empty stomach, you will almost pass out and feel ridiculously embarrassed.
EDIT: Also, for your concern about it being "overplayed", as long as it has meaning to you and you add a unique element to it, don't worry about it. The biggest thing here is not to get something for the sake of getting something. I hate people who are not Chinese but get Chinese symbols, tribal tattoos (what tribe you from? Like really...). I had a friend who wanted to get a cadet pilot symbol on his chest and it meant something to him but instead he got a maple leaf and everyone ridiculed him because he changed his mind and picked out a sketch rather than make it personal.
Like, my next tattoo is a family tree ("original", right?) but I've spent about an hour and a half with the artist on it and we have come up with a unique spin on it and now we can't wait to get in the shop and get it done.
