This question may have been asked before, how does a collector find the value of a graded coin before buying it ?
By graded, do you mean "slabbed" ? The US coin catalogues give values according to the numerical system. If you've got a coin slabbed by a top-tiered grading company (PCGS/NGC), the retail price guide on the PCGS website may help. Otherwise, register for an account at Heritage, and search for similar coins in the auctions.
Even better, get a most recent copy of the greysheets here: http://www.greysheet.com/web_order/currissu_form.asp This will contain the bid and ask prices for many different grades of coins. The bid price is the price dealers will pay for coins, and the ask is obviously what they will ask for coins. Note this is for dealer to dealer transactions, but in retail, you should easily get a price between those two numbers, sometimes even as low as bid.
While not always easy I use heritage to determine what a graded coin goes for at auctions. As long as a dealer is new those prices I find it acceptable. Then the primary and most important part - does the coin warrant the grade? And is the coin have the eye appeal I like? Don't just get caught up in thinking all MS64's (for example) are going to be worth the same price - some 64's will drive premiums and some should not. It is still all about the coin - not the slab.
Short or long answer?? Short or long answer?? Short - look for other same graded coins in magazines, auction catologs, web sites. Long or real answer - learn to grade, look at thousands of coins, spend years reading studing, and then know this,,, The value means very little until seller and buyer meet, agree and exchange $$$ and leave happy. Really I know what you are asking but if I have such and such PCGS coin right here right now worth, (by the books, charts, graffs, auctions) $1000 what that really means is I have a coin that some are buying and selling for $1075, $965, $1100, $890 and so on - until buyer comes over wanting to buy it and makes an offer "it ain't worth *@&%. We live in a false sence of "worth" often times thinking this or that about coins and it's only natural that we do this but until dude comes over and hands me $$$ for my coin do I know what it's worth.
