[chachahut]

When discussing any split with the bar - you must (as Landarc pointed out) make it a split of the profits NOT sales. Unless the bar is kicking in a % for at least the supplies, then your % will be covering material costs PLUS your time PLUS a VERY marginal profit (maybe). Meanwhile, the bar gets pure profit for their %. Better might be to make a decision on how much you think you'll make in profit - let's say you're clearing $3 per item x 200 people = $600 & offer the bar $100 as "rent" for the day.