for me a big part of the 'moped boom' was about 2004,5,6 when 'the internet' happened and Craigslist reached old people in midwest towns. All of a sudden people had a zero fucks way to throw up junk for sale, prior to that you had to take out an add for 15 bucks or whatever to sell your stupid 100$ garbage moped, so you probably jut threw it away.
the first couple mopeds i bought were terrible deals, i had no idea what i should pay for them, within a couple years later i could buy all the nice clean maxis and pintos i wanted for 150 each.
now its quite a bit harder, ebay butcher fucks are snapping up anything cheap and poisoning the pool for people who think their shit is gold now.
but still, if you want it bad enough, you'll get it. i paid 500 for my first maxi non running with a rusty tank... ouch... but still worth it.