Judge the seller and the photos
The seller is as important as the coin. Check feedback, how long they have traded, whether they specialise in coins, and how they describe condition. Vague sellers with stock photos are a red flag; specialists with sharp, in-hand images of the actual coin (both sides, plus the edge) are what you want.
Good photos let you grade the coin yourself. If a listing hides the coin behind glare, a slab-only image, or a single low-resolution shot, assume the seller is hiding a problem and move on.
Understand grading, slabs and returns
For valuable coins, third-party graded ("slabbed") examples from PCGS or NGC remove much of the risk — you are buying a guaranteed grade and authenticity. For raw coins, apply your own grading and assume the seller has been optimistic. Always check the return policy: a no-returns listing on an expensive raw coin shifts all the risk to you.
Beware "gradeflation" and self-slabbed coins from unknown holders — only the major services carry real market trust.
Avoid counterfeits and overpaying
Certain coins — Chinese silver dollars, US trade dollars, key-date rarities, gold — are counterfeited heavily, and a "bargain" on such a coin is usually a fake. Compare the asking price against recent sold prices for the same coin and grade; if it is far below market, there is a reason.
Buy the coin, not the story. Emotional listings ("rare!", "error!", "last one!") are marketing. Verify the claim independently before paying a premium for it.
Check any coin before you buy with CoinVault Pro
Before you bid, run the coin’s photo through CoinVault Pro to confirm the type, estimate the grade, and see real eBay sold prices for that exact coin and condition — so you know whether the asking price is fair and whether the seller’s claims hold up.
After you buy, add the coin to your collection and track its value over time. CoinVault Pro is free to download, GDPR-compliant, and hosted in the EU.