You could try looking at the sites that let the University rooms that students live in during term time, they are cheap and some are based in places like Bournemouth and Cornwall etc so make good bases. Good luck. If you really want to chance it, then go last minute overseas, Kos for example (I work in travel, Kos is not doing great this summer). The cheapest would always be sc so you'll need spending money for meals etc so might still work out cheaper to stay in the UK. Plus Bulgaria is very cheap but IMOP you get what you pay for there.