First time I went to the states (some 20 years ago), for some reason or other my local bank gave me a heap of $2 notes (also some $20 and $50 ones!) when I asked them for a few hundred dollars, just so I wouldn't have to worry about finding an ATM accepting my card at SFO.

Didn't realize quite how uncommon they were until I tipped someone a couple of them and they angrily asked me for 'real money'!

Not that I use much cash but I haven't seen a $2 bill in the wild for a great many years. I could see how someone might be suspicious of them (even if only because they suspected they'd have trouble using them).

I’ve always been fond of the 50 cent piece too. It’s too bad that the ubiquity of the quarter makes it the only contender for a single-coin system.

Some places have free 15 minute parking, which seems like a better setup all-around.