One day tickets?

Have one or two-day tickets ever been made available on the gate? I notice there are tickets for locals but they are restricted to NP8 and not good value anyway (compared to the cost of a full ticket). I live just 20 minutes away and have friends who have picked up on my enthusiasm and would love to visit on Saturday and maybe camp overnight. But work would prevent them from making use of a full ticket.  I guess the only option i can suggest to them would be to try and pick up cheap tickets via eBay etc.

Other than the NP8 residents' tickets there have never been 'on the gate' tickets available SunnyDe. Best bet is, as you suggest, to pick up a cheap ticket from someone who can't go at the last minute.