Here is a listing of threads on the board that include legitimate promo codes, coupon codes, and offers to different online stores:
NewEgg promotion codes
ZipZoomfly coupon codes
Apple Store coupons and deals
MacMall promo codes
HP deals
ThinkGeek clearance items
TiVo discounts and deals
Creative Labs discounts and deals
WWEShop coupon codes and discounts
Busted Tees coupon codes
Expedia coupons and deals
TasteBook deals