If I'm in a month where paying bills is going to be tight or there are more payments going out than usual I write down all those payments and divide it by 4 so I know roughly how much it works out to per week. Then I know roughly how much I can spend on other things and put in the savings account.
New plans have just been announced by the Government
DON'T assume your landlord covers you
Incl £2ish sun cream & £1.50 disposable BBQs