Try the Republic of Georgia - Tbilisi was sensational last year. I spent 30 Euros for the nicest guesthouse in town, the food was excellent, and it's not overrun with tourists. Pegasus Airlines can get you there from London Stansted - probably have to change planes in Istanbul (prices are low).
Istanbul is another good choice, but prices are generally a little higher.
[ Edit: Edited on 06-Jul-2012, at 09:44 by Daawgon ]
If you have no enough budget then I think you will visit city rather then other country. Because cost is depend on destination and on country base. I know it is difficult but from my point of view there is no other way.
I can suggest you to go to Turkey. Especially the south east part were you can find cheap accomodation and nice people. A day per person can cost you 30 Euros per day. It's easy to get there from Istanbul with a good bus network.
And let them suggest the country and what is currently cheap.
can be cheap too.
Note, with the bad weather in the UK, there is a late rush for holidays abroad.
wow! Thanks for all the suggestions, you've all been really helpful!! i'll check all of your suggestions out