Though Listia's rule of thumb would be that 1000 credits equals $1, I believe the demand is much higher for gift cards because they offer a much higher versatility as to what the winner can have in exchange for their credits. In this case, the winner can now buy gasoline with their gift card (but could not win gasoline from an auction because it's not allowed to be listed). Also, I would say since gas prices have dropped down to about $2 a gallon in most places, the demand for gas is a lot higher (though Shell offers many other things rather than just gasoline e.g., snacks, motor oil, cigarettes, etc. -- all of which wouldn't be allowed as an auction listing on here; the winner could buy any of those with this $50 gift card).