Many years ago, fresh out of school, I worked as a programmer for a 60-person company that sold rare coins to investors. The owner of the company started out as a teenager by buying rolls of dollar coins from the bank, sorting out the good ones, and bringing the rest back to the bank. It was not only rarity, but the condition of the coin, that determined its price.
For an example of how condition of a coin can dramatically change the price, see a price list here for 1909 Lincoln cents showing the VDB initials
Look at the price line for
1909 VDB (Lincoln Penny) RD (Red color)
MS 60 (Mint State 60) estimated price $32
MS 63 (Mint State 63) estimated price $70
MS 64 (Mint State 64) estimated price $160
MS 65 (Mint State 65) estimated price $250
MS 66 (Mint State 66) estimated price $550
MS 67 (Mint State 67) estimated price $1,650
MS 68 (Mint State 68) estimated price $20,000
At that site, an almost “perfect” coin - none of the relief is worn, no scratches, etc. would be MS 70 (see their grading standards here http://www.pcgs.com/grades.chtml ) Complicating the fact is that coin grading is somewhat of a subjective business.
If you find a coin in your pocket, there is not much chance that it be anywhere near Mint State.