i got a custumer who might not want to pay the whole price for 100 people so i thought i just tell her to get a sheet cake and it will not have too many decorations so it would be easy for me to make... do you guys think i should sharge the same i do 2.50 per slice?

Charge the same per serving for a sheet or round. Shape makes no difference except rounds are easier to do.

Kory is completely correct re: shape. However - if it's a true sheet cake, which around here means a 2" tall hunk of cake - not torted, no filling, then I consider it a "half-tall" and charge half my normal price. If the "sheet cake" is torted and filled just like a regular layer cake, then yeah, the only difference is shape and it's full price.

what leahs said. plus my sheet cake pricing does NOT include delivery, whereas my round/layered/tiered cake pricing does.