free, just pay postage item 1 - 65 chevy wheel cylinder - I used to keep one of these trucks going for a friend - cylinder is used, looks like it would be fine if you just hone it and put a kit in it - I think we got a deal where new cost less than a kit, don't remember why I changed it. If no one wants it, it goes into the scrap bin. this will fit in a flat rate envelope, $4 postage (it's metal, there's the relation)
item 2 - a spool of what used to be clear tubing that I got from Lockheed surplus sometime in the 70s and never used - the tubing is vinyl, I suppose, of some kind, and now has some white fuzz on it - if I haven't used it in 20 years I probably don't need it - spool is around 12 inches high and about 8 or 10 inches in diameter (it's in my garage and I don't want to go out there now and look at it). Ought to fit in a flat rate box, $8 postage - I was going to use this for fish tank hose, should be OK for low pressure air - at least the price is right - there must be hundreds of feet of this stuff.
item 3 spool of fiber optic cable with ends on it - a masking tape tag says it's 101 meters, LeCoy Research. The cable will fit in a flat rate box if I discard the spool, so $8 for postage - it might fit in a flat rate envelope too, who knows. a tag near each end says "MaxLight".