Well , as someone who has been a picker over 25 years I can tell you that the early days of eBay were some of the very best - if not certainly the best of times to make significant money from stuff you could find at yard sales and thrifts. In the early days of e bay - there was scarcity of many collectible items- so collectors paid much higher prices- I would get $100 on eBay for something that I paid $5 for that today you probably could not sell because eBay became more saturated with goods than the available number of collectors. It was not uncommon for me to find say a 1930s through 1950s wristwatch - such as a rare Hamilton , Illinois, etc. and pay $1 for it and sometimes get $500 on eBay from a higher end collector. Watches like that were given to folks for 25 years service with a company and were sold at yard sales by children or widows as these old timers aged out in the 1990s.
The internet was a double edged sword for pickers- yes it created a larger market because many more people developed a collectors hobby of one sort or another ( almost anything imaginable is collected) - so you had a larger market to sell your stuff; but as time went on- multiples of previously considered "hard to find" items went up for sale and prices of almost everything dropped - not to mention that many of the pawns shops, thrifts, and yard sales started pricing their stuff based upon e bay "asking" prices.
Every Saturday morning I would go out early with a goal in mind of $200 profit in my pocket by 12noon- I did that almost every weekend and often far exceeded- not bad as it was tax free money when you sold, everything sold immediately on eBay if you knew what to pick, and it was a great pastime for me, I learned about every collectible imaginable- values, rarity, and demand.
Pawn shop runs for Cues was a breeze back then - that was just a sideline to my yard sale picks - and a lot of extra income too-- no longer.