I've used it several times email CES which is Mr Wilson! He decides if you warrant a ticket with what you say in your begging letter the cheapest I've had is £20 although £5 cheaper if you're a poor concession! the norm is £25 anywhere in the old lady but sometimes no reply to request which is frustrating & usually it's Saturday morning when the ticket office call you if successful/pick up is leppings lane gate 6 & I notice the lady is still there handing out envelopes on match day/ past experiences suggest about 6 to 8 games a year are possible( there's no means test incidentally!) you can also ask for a poor friend to join you if you're cheeky enough/I've personally got a S/T now but it is an option for the walk up on expensive match days of £40+
Hope this helps