I started collecting in 2017. I am mostly entirely a digital collector as my thrift stores are dead of vacuum action because my city lost its independent vacuum repair shops. In the last 3-4 years I have noticed a big surge in vacuum cleaner collectors and vacuum cleaners in general pulling big money. Most modern 90s-00s vacuums going for well over $100-$120. Rare prewar vacuums pulling as much as a used Corolla. It's insane. Even bags and belts and parts are selling like hotcakes. I have bookmarked many vacuums I want, and just in a couple weeks time between my paychecks, someone has bought it out from under me just in that short of a time.
Shipping rates have gone up many times since I started in 2017 so it gets increasingly harder to find good deals as far as online shopping, but if you keep looking and hammering the sites, you can find good stuff. I keep my acquisitions under $50 but will stretch a bit higher if its something rare or unique. I collect anything I can find a good deal on, or thats rare, or thats strange, or if i like it, or if its free off the side of the road or thrown in a ditch.
I will sell common garden variety vacuums once I get them milked for content, and rebuilt and restored to new, but I will keep any vacuums that I truely enjoy and love, and anything rare or unique that I know will never come up again. You can't hoard everything you do have to prune some out from time to time.
Vacuum cleaners are very robust, they will usually never not work, and even so just need some basic TLC and simple electrical diagnostics. I love plucking Kirbys up for cheap because "they do not turn on" and its because the seller doesnt have the brushroll attached properly to trip the safety switch. I've probably got a lot of the worst condition vacuums you've ever seen in your life and they all power up and run when plugged in.
I even have a 2019 model Hoover Windtunnel that was a store return marked for salvage I got for $25 with free shipping from a returns reseller. It was still brand new to the market when I bought it. I plug it in, the motor surges up and down aggressively or stalls out and it makes my house lights flicker like crazy, and it starts smelling really really bad, but be damned if it isnt still fully functional and operational! The motors are made to take long hours of high speed high RPM use so they are really built to take a lot of hard treatment without faltering.