We have seen a lot of mistakes from retailers big and small (the OW projector "price error" a few days ago), it seems the community in general is OK with just a full refund. I mean a full refund does NOT resolve the matter fair and square. If you think about it, what if you were choosing between shop A and B to buy the same product, because of shop A being cheaper, you bought from there but ended up being told "price error" and provided just full refund. You turn your head to buy from shop B and its sold out now. What if you are sent a second hand one when you bought a brand new item and be told it was a typo/wrong description?
What if you queued for a limited edition of a product hours or even days to secure a place, you finally got the chance to buy it, you clearly saw the system still have stock, but was told "wrong stock" later on that the product was in fact sold out a few people before you. Same goes for pre-orders, you thought you were going to get the item first hand first day on release, but was told "over committed". You obviously can get your full refund, but good luck for a second chance of buying it or at least not until the next shipment.
Consumers have a simple wish before any of these happen: get what they pay for. Do buyers need to pay for the careless of retailers? In what situation can buyers lawfully get what they pay for instead of a full refund?
When it's an obvious price error, it's the purchaser's fault because he wants to take advantage of an obvious mistake.
Edit: It should be satisfaction enough being called "a professional" by Gerry Harvey himself.