If the burglar steals something you get the depreciated price of the object, I think it's the bottom of the depreciation. It should be like 1200. If the buglar doesn't steal anything and the cop wins the fight then you'll get a small amount (<1000) of reward money.
You're right, I usually get $500. Depreciated value makes sense. I got $600 for the $1400 exercise machine. He must have had it a while, can't remember now. At the time I didn't have uni ... Having a burglar strike is a nice bonding experience for the residents of the house, I've found. They can hug each other afterwards and have a good cry ... at least that's what my single mom and her teenaged daughter did the first time I had a burglar. Sometimes they just sleep right through it. Depends on the Sim I guess.