The Free-Market Anarchism Car Bumper
Since you're looking at this page, you may well already know that the bumper sticker in the middle is from here.
Other people are not your property comes from an article by Rod Long, who argues it is the single best one-sentence summary of the libertarian philosophy. Please purchase one (or more) to support Strike The Root. (And if you're a long-time STR reader, you may also remember this back bumper from this article of mine, published in 2002.)
The fake license plate (short for "anarcho-capitalist") was made here.
I bought the "I [love] Capitalism" bumper strip through an ad in the back of National Review circa 1987. I have no idea if anyone makes one like it today, though similar ones can be bought through CafePress here and here.
The "Dont Tread on Me" sticker can be bought any number of places.
Finally, I should note that this is my former bumper. We replaced this car in February 2005.