The Case for Certified Coins
Overpaying
Certification by a reputable third-party grader such as PCGS or NGC only guarantees the grade, authenticity, and that the coin hasn't been doctored. It still doesn't protect you from overpaying. This is a description from a 1912 penny graded by PCGS as MS63BN being sold on eBay at the moment.
"Australia Penny 1912 Heaton PCGS MS63 Choice Uncirculated Rare Key Date Coin High CV Quality Coin professionally grade by PCGS international. Book Value in MS63 CV Choice UNC $1750 - $2750 MS64. Tough to find in high grades This is the actual item that you.."
This is by all measures a lovely coin, problem-free, with underlying lustre, and even toning but is it really worth $1750-$2750? Valuing coins can be done using the NumisTip retail price which shows this coin for only $460. That means you can readily acquire the coin at that price and indeed if you check the sales history of certified coins, an MS64BN sold a few months back for just $375. Obviously they got their grossly inflated values from one of the print guides.
Other guides typically rely on dealer advice for their prices so the prices are typically inflated to help dealers move stock. NumisTip pricing is automatically calculated from past sales so the pricing is impartial and as a result, valuing coins on NumisTip better reflects reality.
Rule 3: Always check on NumisTip coin values before buying