Sell all your product with bitcoin as a payment option. Have a tablet near by buyers scan your barcode with there smart phone and enter the purchase in dollars through there wallet and send payment.
Yes, I saw this in Geneva, Swiss, in some bar, I was eating and guy paid with his tab with bitcoin. First time I saw someting like that "live".
That was my reaction also, and it was also done in no-time and super simple, but i think people will soon enough loose that feeling of surprise when someone is paying with bitcoin, who knows maybein the future we will be like : omg, that guy paid with some printed papers, how weird is that ?!
@op just have a big barcode at register, and a tablet/phone/laptop to confirm transactions, and ure good to go.
cheers