It's pretty easy to see if your belts are bad, just get a flashlight and inspect the underside, look at the grooved surfaces for dry rotting and cracking. You can also take a bar of soap, no pumice please, and hold it on the belt to coat it, then go for a drive to check for a change in noise, confirming if it's the belt or not. If the belts look good, they may just need to be tightened up. You could have a dealer or a mechanic do that for you, or give it a shot on your own. I've adjusted my own belts before, and there isnt a great way get at some of the set bolts to loosen up the bracket though, might be best just to pay.
I have 73.5k miles on my car, and just recently had to have both the belts changed out, they were starting to squeak horribly. For belts and labor it around 120 bucks or so,
Good luck!