So GURPS Lite is free. I've got a link to it on the side of my blog. What else is out there that is free for GURPS?
Official products, I mean, not just fan-created material.
Here is the complete list:
GURPS free stuff at Warehouse23
I'd like to highlight some especially good or broadly useful ones.
Caravan to Ein Arris - and excellent GURPS starter adventure. It's wonderful for introducing new players to GURPS, and I've used it to introduce new players to RPGs in general. Yet it's not without some interesting depth for a group that pushes roleplaying and fights and physical challenges for groups that prefer those. It works very well one-GM one-player, too.
GURPS 4th Edition Combat Cards - also a great item for new players - printable cards with the various Maneuvers you can select from.
GURPS Martial Arts Techniques Cheat Sheet - GURPS Martial Arts has a lot of techniques. This is an at-a-glance listing of them.
GURPS Range Ruler - something we actually keep handy at my table as a tiny short-range-only Size and Speed/Range Table substitute.
Floor Plans 2: The Great Salt Flats - varying sizes of hexes and squares. Including, naturally, the 1" hexes GURPS uses. Technically not a GURPS item, but very useful for it.
That isn't a complete list - I mean you can get GURPS Lite in Korean so you can finally play with GURPS Martial Arts in Korean* But these are ones I've used in the past, use now, or just find nice to have in general.
* Results not actually likely.