I love shopping at StackSocial on Black Friday because, it is like stacking coupons. They already sell apps and stuff with deep discounts or lifetime plans but with these codes, you can save extra on top of that. I caught some ah-mazing steals there last year. This is one site not to be missed for apps.
There are 3 codes you can use with them.
BFSAVE20 for gear and gadgets
BFSAVE40 for Apps and Software
BFSAVE75 for online courses