Roll 2d6
2. Customer who has been waiting for the doors to open, B-lines it to your table and buys 1 of each of your new stuff. 1-3 in 6 chance they buy an additional copy for their friend who couldn't make it who also loves your stuff.
3. Guy who rifles through every thing on your table, asks tons of questions about each item. Complains about various esoteric things, then walks away without buying anything. In the meantime half a dozen people who were waiting to actually buy something gave up waiting and wandered away.
4. Parent with crying child buys something from your table to pacify said crying child. Child temporarily stops crying. Win, win.
5. Cosplayer asks if you have books/prints/toy of the character they are cosplaying. When you respond in the negative they storm away disgusted.
6. Crowd in front of your table is actually line for the table next to you.
7. Fan of your work comes up, chats with you pleasantly for 1d6 minutes. Buys your newest stuff. Asks politely for signature on items (yes, of course!) and goes on his/her merry way. Posts positive comment on their social media about you.
8. Guy who keeps coming back every hour or so to look at the same book. Last second of the last day of the convention he runs up to your table to finally buy a copy. Asks if you can give him a discount.
9. Clueless person who has no idea what your products are about inexplicably buys your most expensive items. Walks away happy.
10. Apparently homeless guy who hasn't had a bath since ever hovers around your table. Lynyrd Skynyrd's "That Smell" comes to mind. No customers for 2d6 minutes.
11. Popular cosplayer comes near your table. Photographers surround her taking photos. Various people gather round. Blocks visibility of your table, no sales for 2d6 minutes.
12. Customer B-lines to your table, excitedly tells you how much they love your work, eventually realizes they mistook you for someone else. Awkward pause, then they walk away. 1 in 6 chance they buy one of your items out of pity, it will be the cheapest item at your table.