I don't think you are a spoiled brat. I help my daughter out quite a bit even though, just like you, she doesn't ask. I do it because I want her to have things she can't yet afford. I would never steamroll her and buy whatever it was without checking to make sure she wants it. The last thing I bought her was a couch. I love buying furniture and what she picked out wasn't something I thought was a good deal or particularly stylish. I bought it because it was what she wanted and she's the one using it so it's her opinion that counts.
You said the gave you the silent treatment for a year over something. That's abuse. Your parents may very well have good intentions but just be a little immature or it could be a control thing. It's hard to say but for sure you have a valid grievance here.