Just in case anyone's booking through the Monarch site, there's a voucher code that will get you £10 off - just enter CHEERUP in the voucher box when you book. Not much but better than nothing
The voucher's mentioned on their home page, but is one of several adverts so you may not necessarily see it - thought it may be handy for some people? Don't know how long it lasts?
Generally too, before booking ANYTHING, it's an idea to google "Voucher Codes" to see if there's any money off through a code.