Do note that a fully unlocked Oxydendrum cost only 5,800 Potatoes, and for that amount you can just get 5 ampies and 1 (and half) manyu.
The amount of Potatoes the red RB will drop will be a lot higher, but to clear out all manyus and all ampies, you'll need a total of 25,000 Potatoes. And that's leaving out the presents.