If you want to vote in Boulder, it will cost you $0.41 to mail it in. I thought that the Supreme Court had made poll taxes illegal - apparently it does not apply to Boulder. But there is an alternative.
No, not driving over to drop it off. That not only contributes carbon to the atmosphere (which is a bad thing) but with the present price of gas, driving even 4 blocks costs more than $0.41 in your SUV (which apparently every other person in Boulder needs).
Just put a 1¢ stamp on the envelope. I used a 2¢ stamp (smallest I had) and mailed it. And my ballot status according to the Clerk & Recorder's site is arrived and valid. So you do have to pay to vote - but only 1¢.
Update: This may be illegal.