There is currently a Borderlands ( 1 & 2 ) bundle for sale at Humble Bundle. You can get both games and a few dlcs for only $15.
Sale: https://www.humblebundle.com/
Current price: http://store.steampowered.com/app/8980/
http://store.steampowered.com/app/49520/
Edit: i just bought Borderlands: The Pre-Sequel for 85% discount (75% from the bundle and 10% from a other coupon i had) :D