There was an explosion of privatly owned dollar stores here then they thinned out. There was one that had really good little clamps and stuff for $1 ea. They were very similar to the ones on this page.
https://www.nelsonhobby.com/clamps.html Don't know anything about them but they are very close to me as in just a few miles away.
I have been checking all the dollar stores for them for a while now. I'm about to just order a case of them from the manufacturer.
For sanding blocks scraps of MDF work great. They are hard and dead flat. I have to order more paper for my t-sander. I have a 3 or 4' one (CRS strikes again). Gotta get it by the roll for it.
For a budget scroll saw the Delta SS350 works well. I picked up a used one locally for $75 nearly brand new with lots of packs of german blades. Best buy on blades is ebay.