Ew. There's laws about what you can do with ashes too. Some people bury them in a graveyard. Some people get a permit and spread them according to their loved ones wishes. Some people don't bother with the permit and just try hard not to get caught. Legally I can't do anything with my grandmother since her son is still alive (my uncle), but he refuses to acknowledge the issue so they are sitting on a shelf in my dining room. My mom was spread at the Outer Banks of NC and my dad was spread at a golf course during a charity golf tournament in his honor. The charity was the Maryland Transplant Resource Center, an organization I still volunteer with. My aunt was buried as was my other grandmother.
And yes, cremation after whole body medical research donation is free. It's not that way for organ donation though. You get the body back pretty quickly, and can have a funeral with the body present, open casket if you want, and then you have to decide what to do with it after that.