This is a long one, but bare with me.
So the one thing we have to determine the value of a $ that I remember, is every time you take money from Maya's board in the early chapters, it's depicted as a 20. Thus, $$$$$, the maximum amount of money you can have, is probably a hundred bucks. When you take out money on the prep balcony to give some to Riona, MC is holding a nice little stack, too.
People keep talking about two forms of currency but there is not. The different color of the money is to specifically tell you what belongs to the DIKs mansion fund and what the MC carries in his pocket.
I'm pretty sure the 5k MC is given as inheritance, is just that. 5,000. MC specifically states it isn't a life changing amount of money. Probably enough to cover a semester for Maya where they can look for a different solution, one option you'll be able to use that money for. Next episode will likely provide you with a different way to use that same money. I also imagine the money is in a bank because people don't get cash for inheritances.
For people mad about the "morality" system, I think your anger is misplaced. It is not about morality. The dik/chick system is an indication of the people you like to be around and how you act affects them. Typically peeking on "chicks" is a DIK move, but not always, sometimes you even gain +1 RP for it. Even Massive DIK MC is a pretty good dude, just a bit of a playboy. He's 19 now and up until he went to college, he had slept with precisely one girl who was his best friend.
Some side notes:
Pretty sure Tybalt has something on Jill aside from anything having to do with MC. Even Bella openly states she hates Tybalt and has expressed this to Jill but it never changed anything.
Jill and Sage are likely related. Sage is one of the only few people to comment on Jill's roosts before Josie starts doing it.
Lynette, I suspect, was a sorority sister of Bella. If she is a B&R, it's likely a Burgmeister.