When seeking out a reputable coin dealer, it's a good idea to do your homework.
Here are just a few warning signs to look for:

• He has lots of coins graded MS75 to MS160
• He calls "slabs" those clear, coin holder thing-a-ma-bobs
• He works out of the back of a 57' Chevy station wagon.
  
• He says he learned to grade coins by watching HSN.
  
• He makes his own slabs out of Crisco hardened in a kiln.
  
• His name is Shifty Two-Face and used to be a lawyer.
  
• He has authentic St.
  Gaudens Double Eagles starting at twenty cents.
  
• He sells Washington error dollars with a rim,but no coin.
  
• He makes his own slabs out of Crisco hardened in a kiln.
  
• He refers to the "Red Book" as that over-rated guide he never reads.
  
• He has a plaque that says he graduated from The New Mismatist School
• He has proof sets where the coins are sealed in saran wrap.
  
• He already has all the Presidential dollar coins, including Franklin.
  
• He has a few rare Roman coins that say 250 B.
  C.
  
• He uses a grading company called the ALTCC (Acme Looney Tunes Coin Corporation)
• He can smokes a cigar the whole time he's showing you his valuable silver certificates.
  
• He only accepts cash and that's with plenty of I.
  D.
  
• He has a no returns, no refunds, no guarantee, and an "I've-never-seen-you-before" policy.
  

Well,you may have your own issues with certain dealers but forewarned is fore-armed.
You might be better off keeping your money under the mattress than working with an unscrupulous dealer.
Check with the Better Business Bureau or, if it sounds too good to be true, run, don't walk to the nearest exit.