An early discount from Time Out. 40% off rear dress circle (£69 down to £41.40) and upper circle (£34 down to £20.40) tickets for Rigoletto, which opens in February 2014. If you're tempted, bear in mind that these are amongst the worst seats in the house, visually and acoustically. Also, you don't find out exactly where you're sitting until the day of the show.
Discount Theatre offer the same reduction on a different range of seats: dress circle (£84 down to £50.40), upper circle (£49 down to £29.40) and balcony (£25 down to £15). These seats are better located than the ones in the Time Out offer, and the price reflects this. The site shows you which seat numbers you've been allocated before you pay.
If you want to book this far in advance, the £20 'Secret Seats' are a much sounder bet. Rigoletto isn't selling that well, so there's a fair chance of getting a decent stalls or dress circle seat.