Money Bags! Multiple uses
 

I found something to be quite useful for many things - bank deposit bags. I first bought a couple for my wife to use one to keep her tip cash in the safe. I used the other one as my commuting tool pack that goes in my backpack or other rack-mounted bag. I've since bought more and put all the important stuff for our car in it so they don't get beat up in the glove box.

Search Deposit Bag Bank Pouch on eBay and you'll likely find the seller I got mine from - they only cost about $3.50 each (sold in pairs).

https://cimg5.ibsrv.net/gimg/bikefor...50c735210e.jpg

My late dad, always reliving his backpacking glory days, used to buy tons of little bags like this, but from REI. They’re in the toolbox section at Home Depot too. He always called them diddy sacks

I've got a bag from Home Depot. It works out pretty well. It holds all my tools, even my mini pump, and fits inside my pannier bag.

Good idea. Been using a fanny pack.