Adding to what red said.
Think very carefully about what your getting, its going to be with you every day for life.
Talk your design over with the artist they might want to alter it.
Get as many recommendations as possible , check their past work.
Different artists will charge different rates and take various amounts of time.
The tattooist I use charges £80 a hour with a minimum charge of £40 . Different areas will vary ie its probably more in London than Glasgow
Aftercare, listen to the advice given to you by your artist, this also can vary.
I've used tattoo balm and bepanthen cream recently.
Don't take pain killers as these thin the blood. Maybe eat a mars bar or have a Lucozade drink before.
Be prepared for the itchy phase about a week or so in n lasting a few days.
Try and find someone you can relate to , a bit of banter definitely helps , take a mp3 player and listen to your favourite tunes when its been done.
Way I'm getting another one next week.
All the best with the new ink