Awards trade so thinly, and most so infrequently, there is no price sheet like coins and stamps. That makes the value of the hunt, and the find, a prominent part of award collecting. Staying in-touch with dealers, collectors, and auctions is the primary way to spot them.
Once found, there is the matter of price. There is some access to historical and current sale prices through the above mentioned dealers, collectors, and auctions. Learn from them, and consider the following:
The bigger the hit, the more cultural impact the music, the more you would expect to pay, or get, for an award. Masterpiece albums, or singles, tend to have more value than lesser albums or greatest hits compilations.
The rarer the award the more value it will have, and the more competition there may be to buy it. Keep in mind, the popularity of most artists fade, and price can be a moving target. The rarest awards of once popular artists can shrink in value, and awards for popular artists of the day, increase.
RIAA awards have commanded the highest prices, especially white mattes from 1964-1975. Their certification and consistent formats have made them collector favorites. RIAA first presentations, manufactured at the date of certification, have more value than later presentations. Early awards and artist presentations were made in very small quantities.
In-house (non-RIAA) and foreign awards are authentic, beautiful, and scarce in their own right, yet they usually sell for less.
Awards in original condition, with original parts, unopened and untouched, fetch the highest prices.
Minor condition issues (especially in older awards) like fading, nicks, changed hangings or backing paper may have little affect on price. Major condition issues like cracks in frames, very stained mattes, or discs that have fallen out of the matting are more serious, and can be restored.
The question of right price comes up with every award considered. Knowing what to look for, and what to avoid, is always the way to find best value.