Extreme Lawnmowing

The Extreme Lawnmower is considered the most profitable and least expensive of any of the blocks by far, needing only 2 upgrade branches for all of the profitability.

Pricing and Upgrades
Extreme Lawnmowing has four upgrade branches that have 20 slots each. They are (in order) as follows:

Mower Bonus - 37 Million ~ to buy final upgrade

Mower Speed - 49 Million ~ to buy final upgrade

Animal Density - 37 Million ~ to buy final upgrade

Berzerk Bonus -  49 Million ~ to buy final upgrade

Mower Bonus and Mower Speed are nearly all of the profitability of the Mower, affecting the idle DPS.

Animal Density is entirely useless unless you are producing fair amounts of Carrots and Turnips which will result in animals producing profit, which the profit is still insignificant as to the DPS produced by the previously mentioned upgrades.

Berzerk Bonus is only recommended to be purchased if you plan on "Anti-Idling" the Mower, which is much less profitable than using "Extreme Poop Mongering" which is the best for "Anti-Idling".

"The Sweet Spot"
The mower is unique from the other blocks in the fact that the way you leave the block affects the blocks DPS dramatically. There is a specific spot where the mower performs best (highest DPS). This spot is different for each single mower. You will have to find it by moving the mower carefully around and looking at the DPS. Keep in mind that a fully upgraded mower (level 20 mower bonus and speed) can get up to 75k DPS if the crackerplier is on 3x.