Shaping your eyebrows is free with a tweezer; guaranteed instant improvement.
So is exfoliating - if too skint for scratchy sponge, use a microfibre cloth from tesco and scrub dry, don't bother with a product, works much better. Slap on moisturiser - e45 from poundland is brilliant - and you instantly feel and look glowy. If you need to save a pound, mix olive oil (not veg oil) and a fistful of sugar and scrub with that and rinse off.
Olive oil all night as a deep conditioner and shampoo off in the morning.
MNetters swear by MUA makeup in Superdrug, which is vv cheap. I always get my makeup free on the front of magazines or from TK Maxx.
Get a free - and surprisingly non-drag-queen - makeover from any Mac counter. Having been deeply cynical beforehand, I skipped out looking well pretty. Shows you what make up can do, crucially before you buy anything.
I dye my eyebrows and lashes at home, which costs about 10p a shot once you have forked out a fiver for the Eyelure kit. Makes a difference and saves buying eyebrow pencils.
This may not work for you, but I always wear scent. Aftershave can be superb if you haven't got any money - it's cheaper and smells expensive on ladies, for some reason.