Oh! Whatever you do, be very careful with brick and mortar coin shops. Most are dishonest. There are professional grading services who authenticate and provide a cash backed guarantee of authenticity and grade. The "Professional Coin Grading Service" (PCGS) is, by far, the most respected and command the highest overall prices. Cost is something like 30-35, and the coin is sealed in a very robust optical quality holder (slab) with the certification info, type, and grade. Well worth it for any coin worth more than $500.00.
I was what is called a vest pocket dealer for a good 15 yrs. A vest pocket dealer is someone who deals coins mainly at coin shows but does not have a physical store.