Prague

Cheap
In English currency it a pint of Beer is roughly 20 pence.
Its also a beautiful city and very romantic! I know flights are cheap in England! I assume your from england. If you need to know anymore leme know.
My 5 day trip cost me only £400 quid with flights, food, drink, spending money and a 2 bed 4 star hotel. You could probably do it for cheaper. As i spent alot of money on drink and eating out.