This could become a great "tips" thread.
I've bought plastic clamps from Lowes for hanging backdrops, etc. Cost a fraction of those sold in photo stores.
I carry a lint roller in my lighting bag to get cat fur, etc., off black backdrops.
Bought a cheap rolling suitcase from Wal-Mart to keep strobes in (yes, I have a problem)
In the old days I used electrical tape to tape two rear lens caps together back to back (very handy for keeping two small primes in the same slot in the camera bag and you never lose the caps, because they are always attached to at least one lens.)
In the category of "you know you've really lost it" – I asked my daughters to buy me a small pop-up deer blind that I put in the backyard next to the bird feeder so I can get closer to the birds.