As far as I know, the whole festival has not sold out. People will be turning up with spare tickets (friends who dropped out etc) which they'll probably hand to touts (who are not, generally, the evil scum that they're made out to be!).
With supply exceeding demand, I'm pretty certain you could pick up day tickets for £50 or less, either outside the entrance or at Paddock Wood train station.
However, there's obviously an element of uncertainty.
If you live nearby (e.g London) and are keen to go, I'd chance it. Sounds like Morrissey is on top form at the mo, and the situation will be much better than Glasto (sunset headlining slot, enough time for a full set, no bored fans hanging around for the next band, a warm summer's evening with no rain or mud - it's set to be an epic night).