The gengar deal was stupid in my opinion. You can find a gengar with 29-31 in speed and sp atk and have it do the same job. 15 more defense and hp or whatever should not give it a 500k price increase.
However, why in the world are you going off on prices and what not if you haven't even finished the game yet lmao? I can get 200k by just training pokemon up in dragon's den in just a couple hours or so. Albeit I have membership, but even halved that's still substantially better than what you were going off of.
Right now membership just decreases time of leveling and money gain. Unless you really want to make a ton of level 100s leveling is a non-factor considering you can get like 50k exp a poke in DD easy. Money can get you some nice pokes, so can hunting for them. I've found a few comp pokes in just a couple weeks.