Just pre drink as much as you possibly can, within reason. Own brand supermarket vodka is pretty cheap and gets the job done (wouldn't drink it neat though as it's disgusting). Can get a bottle of vodka and a 2 litre bottle of coke for about £13, and that's enough to get drunk off for about 2 nights. Saves on the amount of drinks you need to buy when you're out.
Join discount sites such as studentbeans.com, they always have loads discount codes for everything you can think of, great for a night out or for a discount on your food shopping!
Well it does help if you are a bit of a lightweight like me haha I've actually come home from a night out with more money than when I left, amazing when counting my purse the next day ha (do not know how it happened...perhaps I should of checked my bank statement!!)
I can't stress enough doing predrinks. I normally get a bottle of vodka and mix with lemonade. I make sure I am very tipsy before I go out (but still in control) then just keep my alcohol levels topped up..normally I only have to buy one drink and some shots. But I dont normally go into town till 10.30/11
I found the other day at a b&m store (okay you have to be pretty lightweight for this..) bottles of VS so like knock off WKD for £1.69, the 70cl bottles which is a hell of alot better than the £3 a bottle in tesco!! so yeah have a look in stores along the same lines, stuff wont taste as good but if youre only wanting to get drunk then it doesnt really make much of a difference!