Fast Upgrades is a Special Mission in BTD5 unlocked at Rank 40. File:Monkey Dollar.png500 and File:AwesomeIcon.png75 is awarded upon completion. As per the description, this mission will upgrade all your towers once for free at the end of the round. Note that the sell price will NOT increase with the upgrade. Also, the first path will be upgraded by default unless the second path has MORE (not equal) upgrades than the first.