Hamfests AKA Electronics Flea Markets seem to be dying out, but when you can find them, they are excellent sources for odds and ends to fill your parts bins at home.
I tell friends you can see state of the art equipment at them, just pick the era they were state of the art.
Two schools of thought on attending hamfests, go early to find the one of a kind items (you can never depend on what will be available) and go late to get the best deals as prices drop to move product. There is a third, where you pick through the dumpsters because some people will be bringing equipment to sell and if it doesn't, instead of bringing it home again, they'll throw it in the trash.
Another tip is to walk the entire site first to see what is available and what prices are. Not all will be selling for the same price, and then go back to the vendors with the best prices.
Don't be afraid to haggle.
Personal story, one hamfest I attended had computer controllable laserdisc players pulled from arcade machines. Several vendors had them stacked to the ceiling and at the time, asking for $150 to $200 each. At the end of the show I was walking out and stopped to look at one that included the programmer's manuals. They had not been selling, so the vendor asked me to make an offer, I opened my wallet and said I had $45 left, the vendor yelled, "SOLD!" and I walked out with one. They were never seen again, so I was very happy I had picked one up. I still have it and have written programs to control it, even though I ended spending $80 for my first laserdisc to verify that it worked. The vendor said it would play CAV laserdiscs, but was unsure if it would play CLV. CAV allowed single stepping, but most discs were CLV - long playing. After finding a CAV copy of Bladerunner and it worked, I bought CLVs of other movies and found it worked as well. One of the best deals I've made.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.