Budget Battery

 is an upgrade in the Military Monkey Knowledge tree, added in Version 6.0. It allows the Artillery Battery upgrade to cost $600 less regardless of game modes. It requires eight military knowledge points invested, Paint Stripper, and a one-time purchase of 500.

Prices
The following are prices for the Artillery Battery upgrade with and without the effect of Budget Battery:

Summary
Mostly for assistance of buying early Artillery Batteries and for Artillery Battery spam.

Tips

 * It makes it easier to spam Artillery Batteries, as well as make it easier to use Mortar Monkeys as major DPS against MOAB-class bloons.

Trivia

 * Budget Battery is the first new discount-related MK to be added into the game.