I personally wouldn't be keen to make POP days common - I know its been common practice for years in America but if you have standard prices then a POP option the single ride prices will sound expensive.
I think you are best to do a POP on one night of the week when trade is poor anyway so its still a special offer rather than the accepted norm.
Another thing that as come quite popular here is all rides at one pound - some even do it for the duration but again seems to be most effective when its just one night of the event. The Eastern Counties of England have done it for years and the people really flock on that one day as I have seen at Kings Lynn, Peterborough and Great Yarmouth.
Lincoln started doing it a couple of years ago. They picked a tuesday and it was a massive sucess it really brought the people out on that one night and the fair was very busy. The system was it was £1 to get in then £1 for every ride apart from 2xtreme Capirola at £3. But the main thing was it didn't have an effect on the friday nights trade which was usually ok or the weekends which saturday day time at least was slow anyway.
Maybe its something that has been tried already in America but maybe all rides $1 as in $1 per ride might be the headline grabber to get peoples attention. They might end up spending the same cost as a wristband but the point is they don't see oh I have to pay $20 - $35 first.
Times are hard for many people they are watching their money and entertainment is always the first to get cut over the likes of bills food etc. The good thing with the $1 for $1 ride system is people spend what they want to spend. You can cut the rides very short - 1 minute - 2 at most when busy and they won't mind because its a cheap ride and the queues are hopefully long anyway they accept it.
But the key for these things to work is do it for one night a week not every day. Doing it every day just spreads the people across the week. For a $1 night to work you need sheer weight in numbers. A good selection of high capacity rides to swallow the numbers up - Boosters, Bungees, Speeds etc are no good at these nights they don't have the capacity to work alhough those kind of rides being on $2 - $3 do seem to get accepted by the public on a $1 night as does Dodgems being on $2 per car (effectively $1 per rider if they share the car).
Has this been tried in the States? I know tis ride tickets over there but again $1 per ticket, 1 ticket per ride its still the same you still adviertise for one night only att rides $1 * except Dodgems $2 per car, Super Mega Thrill Machine $3.