If Stan had so much money, why would he need to share his appartment? To be able to creep on his female roommates?
You just described the "Louise Perspective" perfectly. Because, that is definitely the way she looks at things.
"Fuck you I'm not paying more money to that pervert. He has got a ton of money anyways, and he steals our underwear and jerks off in it. (Cat actually stole it.)"
Optimistically In reality, He gains both money and company in the rental arrangement.
You have to realize that he doesn't leave the house to go to work. He does that remotely. He also doesn't seem like a popular person with a lot of friends either. Have you seen anyone ever visit Stan? No... Have you seen Stan coming home from a party or anything ever not counting something Lena twisted his arm to go to? Never...
When he makes a new friend, such as with Holly, that is directly because of his room mate situation.
There are of course drawbacks to his plan, and it can be looked at from the pessimistic perspective as well.
Jeremy is probably a massive drawback to him. Imagine Jeremy from Stan's perspective. Some huge black dude you don't even know coming over your house fucking the women there at odd hours, and I'm sure Louise has talked shit about Stan to Jeremy, so that will make Jeremy a dick to Stan if they ever interact. Jeremy may even beat his ass and wind up in jail over it.
Lena has the 1 scene where she hears Louise and Jeremy going at it. I'm sure Stan may has encountered the same with Louise, and that may be why she is so nasty to Stan.
Not to mention all the other fellas Lena may bring over. Ian, Robert, Mike etc... We already know Stan peeked through the door at that sort of thing. So, there is an argument for him being a creeper.
On the other hand... There are arguments in Stan's favor about him spying.
How about you don't fuck when your room mate is home?
How about you lock the door?
How about you go over that dudes house and bang he doesn't have room mates?
How about you put a sock on the door if you don't want to be disturbed?
With Mike Lena can't because he got the girlfriend...
With Robert... No excuse I think he has his own place, which we never visited as Lena for some reason?
With Ian, well he has Perry there...
With Jeremy, I think he lives by himself, but again we never saw his pad so we don't know his living arrangements.