I have noted quite a few comments regarding auctions. Query: How is one to determine a legit/good auction from another?
The best way is to know what you are bidding on - in other words be familiar with the coin in question. For those who are inexperienced - this is of course difficult. So the next best thing is to be able to have a level of trust in the seller. Another way - is to ask others who may have the knowledge. But don't just trust feedback or take one person's word regarding a seller - ask around. Try to find out as much as you can from as many people as you can. Forums like this one are excellent resource for information on sellers and on specific coins. But you are always going to get differences of opinion. So the best way is to do your homework. Try to learn as much as possible about the types of coins you are interested in collecting. Books are excellent resources - so is the internet. There is an amazing amount of info available on the net. It's easier when you start out to stick 1 or 2 types. And as you progress to move on from there.
Another suggestion is knowing your venue. Some internet auction sites are better than others. Some traditional auction houses are better than others. Some days are better for buying than selling. The list is long, but still boils down to learning all that you can. Too often collectors feel the need to rush when buying or selling.