[buymycards]

OK, let's get down to the nitty gritty. This doesn't have anything to do with comfort levels or lack of technical knowledge or chargebacks. It is plain old tax avoidance. (evasion?) The seller probably doesn't have a sales tax license and doesn't pay sales tax on the sale. The seller also probably doesn't report cash sales, so they are tax free.

If you have a sale of $1000 in cash, you have $1000 bucks to work with. If you accept a check, or paypal, or a credit card then it breaks down like this:

$1000 in sales
-15 % in federal income taxes
-5% in state income taxes
-5% in state sales tax
-15% for the employers share and the employees share of social security and medicare
This leaves the dealer with $600 to work with.

That is why dealers only accept cash.