Yeah, I assumed I'd have to pay SOMETHING on my free day -- I just wanted to confirm that a one-way is treated the same as a "local" rental. It would appear that it is, which obviously makes these certificates more valuable, since one-way rentals are almost always much more expensive.

There is, of course, always the fees/taxes issues on "free" rentals. I've been doing Hertz #1 Club free days for a few years now, and they've always computed these fees "humanely" (usually lower than what the website says the cost will be). On the other hand, I had some Avis "free day" certs that I had to complain about -- and switch over to simply " dollars off" certs -- because they kept pricing the "free day" at crazy prices (like $150/day), and then wanting to charge me the tax (which was usually more than 1/3rd) on this rate.

So you never know. Car rental pricing is strange, and "free day" pricing fits the pattern.