It’s hard to say how much the tattoo will cost because all shops are different. If you’re talking about a tiny tattoo than it depends on the shop minimum, but if you’re talking about a tattoo that’s gonna take an hour or two it depends on the tattoo itself and/or the rate per hour.
If you’re good at art try drawing out your own tattoo, but usually you can just bring in pictures or tell your artists your ideas and if he/she is good, they’ll be able to draw something out for ya.
(Go to the source for good tattoo pictures and ideas)