check eBay, I’ve gotten quite a few $100 gift cards for $80. Some (most?) sellers limit the number you can get per transaction. I believe it was a limit of 3 the last time I got some.
I just bought a few off raise.com They were only 8% off but better than nothing. A couple weeks ago they were around 13% off so there must be demand for them now?
Raise.com. Safe and fast. 10% raise cash back right now or up to 8.5% discount on Cabelas gift cards. Then buy through your activejunky.com link and get another 10% back (only 2 on ammo and 1 on firearms I think).