just get the tat artist to draw it for you, that way you know they'll be able to recreate the drawing. if you get someone else to draw it and then take it in, chances are it'll be more difficult for them to duplicate the style. it shouldn't cost much extra above and beyond the cost of the tattoo. just ask them how much they charge for it.
Tattooist will be happy to draw one up for you. They'll also be happy to work with a drawing you bring in. Just be open to them altering the design a little. They're trained tattooist who know how to translate things over to skin; what looks good on paper doesn't always work out on skin. It shouldn't cost much above and beyond the actual tattoo. You'll probably be asked to leave a deposit and come back in a few days for the sitting(to make sure you're serious and not wasting their time and art supplies). Most shops have a minimum charge of $50-100(you generally get what you pay for), and move up from there. Cheers
Depending on what you want drawn, I would ask the artist to draw up what you want tatted on you. You should have some idea of what you want done, and a sample picture of an idea often helps. If the artist is good, then they should know how to do it. That's how I got my Japanese art done on my legs. The artist drew each one out beforehand.
Ive been tattooing for over ten years, we charge 50$ for a drawing that will take over and hour or so to draw, if its something tiny that wont take me long at all then I don't charge anything. the only reason for a drawing fee is if I spend a couple hours on a drawing and all I took was a deposit, then I'm the bad guy if the customer cancels and I don't give back the deposit. There is so much art on the Internet just google what you want then take it from there....
Like everyone said... go to the shop where you want it done... and see if the tattoo artist will draw something up. Most tattoo artists are very excited to do custom work. And don't be afraid to let the artist know your opinions.... a lot of people make that mistake... they just go with it because they don't want to hurt the tattoo artists feelings, but if you don't like something, let it be known. You are going to have it on your body forever.