I just found a Spongebob 3818 set in the thrift store recently for $4 and built it out the other night. It was only missing 1 basic innocuous piece that I'll replace.

I've found a decent amount of Legos at thrift stores here. They're not always priced for me to resell, or may be partial used sets, so I only buy the right ones.

My best find was a sealed new Harry Potter set for $10 and sold it for about $575.

I also found these sealed new sets OUTSIDE in the curb recycling, since I focus more on that these days.

Also found this partial monster in the recycling and sold it for about $151:

Also 75 pounds accumulated from a few hauls on the curbs... I removed a TON of minifigs and accessories I'll deal with later. 35 pounds were at one time. I also have several bags of sets from the curbs with instructions I have yet to validate (mainly for fun) and sell.

These minifigs in the recycling:

Endless examples, just showing some Lego porn off the top of mind from what I've posted before.

I think it's probably a function of the cities we're in. There are many spoiled brats with way too many sets of expensive Legos here.