It is a bit cheeky, but I have always wanted to do this. I went to one of those more upmarket shops that exchange goods for cash (no prizes for guessing who) and I bought two items namely a pair of binoculars and a pair of two-way radios.
So, I paid R199 for the binoculars and R299 for the radios (no bargaining seems to be allowed here). The very next day I took these exact two items back to another shop part of the same chain to see what they would buy them back at. A measly R70 for the binoculars and R100 for the radios (quite a bit of bargaining went on here).
I declined their offer to buy the items from me and promptly listed them on a bidorbuy one rand no reserve Crazy Wednesday auction. My guess was that they would go for R150 for the binoculars and R250 for the radios. I was not far off at all. They actually sold for R160 for the binoculars and R260 for the radios (seller needs to subtract bidorbuy fees off those amounts).
I must say I was quite happy with those results. It means some one wanting to sell their goods gets a much better deal selling them on bidorbuy than using one of those shops (even if they are quite desperate for the money i.e. using the one day Wednesday crazy auction). Also, the buyer is getting a better deal than they would have if they bought the goods directly in a shop.
That is what I like to see. A win-win situation!