PSA/DNA Price Guide
 

What is your opinion of the PSA/DNA price guide for autographed baseballs?
Are they representing a fair market value? If not, are there more reliable price guides?

I haven't seen the PSA/DNA price guide but based on their track record with the SMR, it may be shaky. eBay and other auction houses are good barometers.

PSA's price guides are often out of date. Their card prices are often way low as they aren't updated. It may be something to refer to, but I wouldn't use it as your sole guide to prices.