Money laundering is definitely a possibility since you can buy amazon gift cards directly from PayPal. I also think some items (not necessarily these gift cards) are being used as placeholder items for a product or service (drugs, etc). For instance I saw a very commonly available $2 bottle of salad dressing go for $20 the other day. I was intrigued and saw that a lot of items from the seller had sold for mulitples of their market value.
This is interesting. I would expect eBay fees to crontradict the utility.
How much does your money launderer charge?
I saw a presentation at qcon last week by PayPal about contraband detection using image recognition, the example was a rose for 650 dollars. In the image was a handgun, in front of the roses. So that is a thing, and pp certainly has efforts to stop it, I assume eBay does too.
It's not money laundering, who would launder $300?
Stolen credit cards, online bank accounts, PayPal accounts, etc are available for purchase. Not everyone is as rich as you where $300 is something to laugh at.
I think you are using different definitions of laundering. turning drug money into legitimate money in a bank account is not really useful for these small amounts, but turning stolen goods into cash is.