Jim, there are dozens of reputable, well-known and long-standing coin dealers with internet stores (not eBay). Here's a short list: Liz Coggin David Kahn Rare Coins Northeast Coins West Coast Coins APMEX David Lawrence Rare Coins Eagle Eye Rare Coins Gerry Fortin Rare Coins Now, which dealers of these and many others might suit your collecting needs and desires is up to you. I suggest just looking at websites until you find a dealer(s) that fits your needs and then start a dialog and a relationship. Another resource is to use Collectors Corner to find coins and dealers you think suit. https://www.collectorscorner.com/Coins/
You don't want to buy ANYTHING from the hucksters I have seen on TV. I watch them for about 10 minutes for the entertainment value. I know of a token and medal guy who is a conservative grader, but he now sells almost all of his stuff on eBay. As for coins, it depends upon what you want to buy. Check out the list above from @Publius2 . The trouble is most everything sold on the Internet these days is not cheap. The really common coins that sell for low prices are not worth the effort for the dealers.
I had wanted a high grade 1794 cent for a long time. I overpaid for this one, but it's really pretty. This is an S-21, and it used to be in the collection of the late Dan Holmes. This is just too elegant to be just a cent.