Jim Jones -- My NY Knicks Hat Cost Me $1,500!!!

Jim Jones is wearing your rent on his head -- seriously ... 'cause the rapper (and huge NBA fan) tells TMZ Sports his couture NY Knicks hat ran him a cool $1,500!!!

So, how can a baseball cap get into the 4-figure range?! Don't worry, Jim explains ... and it all has to do with a famous designer who specializes in custom dome-pieces.

In fact, the guy behind the lid has made custom hats for Kanye AND Jay Z ... and some of his headwear sells in the $2,500 range!

And you thought $37 for a lid at Yankee stadium was expensive.