Should I replace a bent axle? Who to buy from?

I was following my RZR 900XP on a 4 wheeler the other day and noticed the left rear axle was moving up and down while spinning. Not bad just about a 1/4 of an inch as it went up and down. I don’t feel anything while driving. Should I just pick up a replacement to carry just in case it does break or does it need to be replaced now? Who has the best deal on them?
Thanks
Guy