I have added the ability to buy a discount coupon from www.codeshirts.com
using bitcoins. I wasn't really sure of the best way to go about it but in the end decided to allow the purchase a 1/3 off discount for 200 bitcoins. The discount code is the bitcoin address, it becomes active when the transfer is confirmed.
What I would prefer (and may work on in the future) is the ability to buy an arbitrary value coupon at the current exchange rate. The reason I haven't implemented it this way is that I don't want a customer to be able to use only bitcoin to order and magento's coupon rules don't really allow me to set it up as I would need. I really like the bitcoin idea but need to make some "real" money too
I think using bitcoin to buy discounts might be a good way to go, exchanging something virtual for something else virtual might be a way to get away from bitcoin being classed as "money" and any issues that may bring with it.
A quick question; Will there be any way to remove a bitcoin address in the future (assuming it hasn't been used in a transaction)? I can see myself ending up with alot of "useless" addresses from people clicking on the button (which generates a new address) and not following through. I'd like to be able to prune these addresses at a later date to remove some of the clutter.
The irony of using a pseudo-anonymous digital currency to purchase an item that links to your digital identity hasn't escaped me