The $1.25 to $1.50 jump is where I ended things. Early to mid 90's. Spider-Clone killed my interest in my favorite books, Captain America had already gone downhill, and Batman's 4 year knightfall/knightquest/funderal for a bat saga just slowly got old.
Currently dropping about 5-8% of my income on comics, mostly ebay auctions when I see something I like. I don't buy new comics, I keep trying to get back in, but just don't find much to be interesting, and the books seem expensive at $4 each. Although a friend did lend me Saga, which seemed decent.