Posted By:
MarkWhen I collected in the 80s, it was difficult to find people to buy from, or sell to, other than dealers.
Dealers would buy back a card they had sold for a mere fraction of the price. I recall many price guides of the day reflecting this, showing both a "retail" (sell) price and a "wholesale" (buy) price (typically half of the retail price). I would have never put any serious $$ into the hobby under that system.
In my opinion, the internet (mostly eBay) made it easy for non-dealers to buy and sell cards from each other. The result was a marketplace where cards are valued without a retail-wholesale distinction, so it's possible to buy a card with the expection that you'll get more than 50% of your money back.