Should i put my foot down?

my next door neighbour keeps on asking to borrow things of me i never used to mind cause it was only every now and then but lately its been all the time and its everything the other day she asked if she could borrow some cooking oil and buy me some more i still havent seen it yet also she asked if she could borrow my nail varnish and i havent got that back either do you think i should keep lending her things or tell her i havent got it cause its absaloutly everything. i once asked if i could borrow some toilet paper til i went shop later and she gave me three squares i just thought how cheeky.