90% of my hats were either free (~30 event hats, holiday event rewards, tons of hats from christmas gifts and trick-or-treating) or cost 1gralat (2011 Halloween and Christmas hat contests, promotional hats, etc).

I only have probably 30-ish hats that I actually paid a lot for: nexus/revolution, some Onnet holiday hats mostly 2011. I only buy from other overworld shops if it comes in black.