well, you have to figure, out how much you would save on shipping to me thats step one. so with shipping you want to figure how much it would actually cost you to send 75 to 100 all in one shipment vs shipping 1 - 100 times, (dont forget to figure in packing too) - pass those savings on. Next you need to figure, are you saving money by printing them in bulk? if so you can pass on those savings. Also, figure in listing this item 100 times, so there is $20 that you can pass on in savings. Figure how much time it cost you to list the item and how much you expect to be paid an hour, so if it takes you five min to post the item then based on 100, you are saving your self 8.3 hours of work, you may also pass on those savings. After all of that figure if you are willing to put out a few more extra % points....