I wouldnn't paint worktops - they take a lot of abuse with hot pans, cleaning agents and so on.
Replacing the worktops need not be expensive - have a look at the prices in your local merchants. Even the cheapest will look a lot better than old, tired ones.
I have seen very attractive worktops made from a mosaic of tiles which had been got very cheaply (mostly free) from the tile shop who was getting rid of broken/ex-display tiles.
The grout and adhesive can add up alarmingly though.