If you're willing to work out something beyond a dollar a card I would consider it, but it costs one stamp out and another to get the card back, not to mention the card & envelope costs. To sell for a dollar is a losing proposition....
I have always used around that same price as a bottom line mark, thinking any signed card should at least be worth a buck to someone. The price of 2 stamps. I didn't actually calculate the added cost of any time, the cards themselves, supplies or anything else, just the largest and move visible out of pocket cost incurred by sending off a card.
Sadly, I found that there are plenty of cards, both TTM/IP and even certified that aren't worth that same buck to anyone. The cost of shipping isn't helping either, at over $5 a package these days.
I still like the $1 range as a good benchmark, but think of guys who get cards signed IP that have nothing but a few cents and their time into them. They aren't even spending the stamp $. Signings and TTM fees are driving the prices of some cards upward a bit, but I still think $1 autographed cards are easy to find (for now).
