What I've been doing lately is each time I go to my nut and bolt supply, If I'm buying a few bolts for a project I'll buy a box of 100 or 50 in that size if they aren't to pricey and then put them away for later.
Nylocks, regular nuts flat washers and spring washers are cheap to buy by the box so I have a fair variety of them.
I got a bunch of storage bins that bolt to the wall from Aldi supermarket. they regularly have some neat tools and goodies on special.
You can see them hanging on the wall in this pic.
