Normally I'd recommend that you save or invest it. However, if you are riding a motorcycle without boots, then I highly suggest spending it on good boots.
Here's a story. In the early 90's, I had a crash where I shattered my right scapula. It healed nicely but it will never be as strong as it was and it always hurts a little. Most of the time I don't even notice, only when I really use that arm. Then I started thinking about what would happen if I really damaged a foot. I always use it. So I bought a pair of Daytona Security boots. They only cost $600 in the early 90's. I'm still using those boots so I've already gotten my money's worth.
So get boots and any other protective gear that you are lacking. Some day you'll be really glad you did.