Prague is a lovely city for a cheap break, with fantastic reasonably priced hotels and cheap food and drink, it's one of my favourite city breaks. This is a great value 2 night/3 day deal for under £75pp.
This deal leaves on Sunday 9th October and returns on the Tuesday 11th October but the good flight times mean you have a full three days. I've picked the hotel Adler Hotel as it is right where you want to be, and is a good rated and recommended hotel. You could find much cheaper too, but I think this is a good value option where you can walk to most attractions.
Fights for 2 with Ryanair £66.96
Book hotel with Expedia using 10% off code on HUKD £80.55