you could offer different types of your nail services,
like a quick mani, standard mani, luxury mani - same with pedicures.
for acrylic nails on my price list i've got t&o, nno, plus extra for embedded decorations or coloured tips/glitter forever french.
nail art you could do different prices eg. fancy french polish, freehand painting, gems, glitter, foils?
hope this helps you a bit
& good luck with your nail art course, i loved doing mine, didn't want to finish it! x