I'm going to get sketches for my first tattoo on friday...what to expect?

on friday i am going to get sketches done for my first tattoo, it is somewhat challenging because i want it to look like a painting of cherry blossoms..so i don't want outlines or anything..kind of like a pastel or watercolor painting of cherry blossoms on my side. idk what good 'etiquette' there is to getting sketches done at a few places. how much do they cost? do i tip? will the measure me? how many places should i go to and can i let them know that i am going to other places as well? idkkkkkk what to say!! help=]