Grassroots Motorsports. I got three free years for giving them some of my old parts for their latest 911 project. It's a great magazine for gearheads, particularly on a budget.
I've been doing more online reading and forum trolling concerning new cars. R&D, C&D, Automobile are all very good, but when it comes to the internet, free is free.
Here is an interesting alternative to magazines piling up in the family room.