I guess I spend a bit more than some OP, but we do splurge a bit at Christmas, and it includes a stocking from Santa. Santa only brings stockings in our house. Tree gifts are from family. If neccessary, we've done none/one/only homemade gifts under the tree, but we always do stockings, even before we had kids!
DH Stocking
Wall-E (got it on Black Friday, basically free because I was buying enough DVDs for extended family)
2 Sharpies markers
Crank flashlight (needs no batteries!)
Guitar wall hanger (to hang his guitar on the wall for easier access; pretty inexpensive, $10 or so)
Guitar picks
Gumballs
Peppermint stick
Chocolate
Mini bottles of alcohol to add to Xmas morning coffee... probably kahlua and Bailey's Irish Cream
Soap
Under Tree
Beard Trimmer--DS
Fedora Hat--Me
Obama book--DD
Sweater--Me
Stuff I've done in other year's that's done well:
Rubix cube
Sunglasses
Scarf
Hand warmers (disposable or like this:
http://www.amazon.com/Platinum-Catal.../dp/B000CGG5EC I bought metal ones for my brothers a few years back and they were a big hit; but I know I didn't pay $16 each!)
Coffee sampler to try different kinds
"Fancy" shaving cream (heh, in those pre-beard trimmer days, obviously!)
Mix CD of music we love
Quarters for his favorite video game (when we lived in the dorms and had a game room in the basement; I taped them to a pic of the game)
Rented PS 2 when we couldn't afford to buy it but he really wanted to play it; he was a little annoyed when he thought I had spent that much, then I explained it was rented.
I've also heard of people checking out books from the library for one another, things they choose for the other person. Checking out 2 copies so you can read and discuss together seems like a great no-cost option!