7-11's don't sell those calling cards near the cash register because they want to help people. They do it because there's a nice markup and they sell. But prior to them doing such, some salesperson approached the store and convinced the owner that if he were to offer these cards, he would enjoy x profit. Correct me if I'm wrong, but some products are placed in stores without having to go through corporate--these cards being one such animal.
That said, a reasonable 5% fee on the change given to a customer in the form of Bitcoin may pique a shop owner's interest. No risk! Now here's the good-rub
. After a short period of time, the shop owner is going to want some of those coins back to boast his sales. At this point he'll be versed enough in Bitcoin to make that leap.
1. Give change with Bitcoin
2. Start accepting Bitcoin
3. You want a Slurpee with that?
~Bruno~Fake Edit: I thought this was the cat thread.
Real Edit: Here's the selling/marketing point. The shop owner will think that he's now a banker, charging a fee to give change. It's doesn't take him too long to realize that he can make even more by selling Bitcoin. At first, he may refrain from accepting Bitcoin for purchases, but he can always do that later once his customer base reaches a critical mass and starts demanding that he so such.