This is NUTS! If I had the cash, I'd do it though!

If you wanna party with Diddy at the Playboy Mansion, you better be freakin' LOADED -- because TMZ has learned, tickets for the rapper's post-Grammys after party top out around $50,000 each.

The cheapest ticket is a slightly more affordable $1,500 and they go up from there -- $15,000, $25,000 ... all the way up to $50,000 -- depending on what services you may require at the black tie affair.

Sources connected with the party promoters tell TMZ, the $50,000 Monster Cabana ticket gets you 2 cabanas, VIP admission for 20 people, buffet dinner, open bar, free bottle service ... and 15 dedicated female promotional models.

Thankfully, it's all for a good cause -- the party's proceeds will go to benefit the Angelwish Foundation for children afflicted by HIV/AIDS.