I'll throw out a couple of more items
Legos - they're great for making molds if you make your own resin parts and can be very handy if you need a jig to hold a model at a certain angle while you work on it.
Butter/Margarine tubs - I've used them for years for parts storage, as a water container when I'm sanding and the tops are great for mixing epoxy on.
Another item I've found very handy for storage is the round plastic container that electricians tape comes in - they're great for storing the uninstalled parts on a particular model and don't take up near as much room on your desk top as the origional box does.
Another thing is, don't think you have to buy everything you use at an LHS or Web Store. Take a look in the crafts section of Wally World or K-Mart. Browse around in other sections of Michaels or Hobby Lobby (you can find some really nice camo netting in the fabrics section). I buy my enamel reducer in bulk at the local auto supply store ($20 a gallon vs about $48 for the same amount in the small bottles at the LHS). I just bought a set of very fine nosed flush cutters at an electronics store for $5.98 - they were on close out. Check out flea markets and yard sales - you'll be amazed at what you will find in kits, tools and supplies at reasonable prices. Even go dumpster diving (try and get permission) - I managed to salvage a piece of safety glass that went on top of a very large desk (it had one corner broken off of it) out of the dumpster at work - cost me 10 bucks to have it cut into two 24 x 30 pieces w/the edges flamed to round them - one is on my work surface and the other is in storage as a back up. The stuff is out there, all you have to do is figure out what and where.