Riga is atttractive, popular and cheap.
There's lots of information here:
http://www.virtualriga.com/default.asp
(The 'Prices of Goods' page quotes about 35p per pint for beer. Meal prices work out at roughly in the range �1.50 to �3)
Ryanair fly from Stansted & Liverpool. As a guide to flight prices, I've just checked what they're currently offering for a departure on Friday 1 December with a return on Monday 4 December. The prices are �9.99 out and �0.01 return (+ taxes and charges).
The airport is only 7km from the city centre. A taxi only costs about �4.
Cheap enough for you?
Chris