been invited camping for a weekend. im a total plank about such things so what will i need?

[mamazon]

for me and 2 children.
my brother has a 3 man tent which i am going to pinch. its small but i figuered its only for sleeping on so not such a problem.

we are meant to be going on the august bank holiday weekend for 2 nights.
what are the essentials i need and how much do they cost. everything needs to be as cheap as poss or we wouldn't be able to go.

TIA

wind up torches and lanterns are great, get them everywhere now even pound shop for torches, great if you fall asleep with them on. Poundland also do a 24 led tent light, its light weight enough to hang up and supposed to have hours of light

But will need a torch for loo trips etc.