Thankfully, there are a few things you can do that don't involve you needing to spend a fortune. What's better, you probably already have most of these items at home already.
Toothpaste
Pop a little whitening toothpaste onto your nails and rub it on them. Leave for a little while and brush away with an old toothbrush.
Lemon juice
Put a little lemon juice into a bowl and soak your nails in it for about five minutes. You can also soak a cotton bud into the lemon juice and rub it over your nails.
Baking soda
Rub some baking soda onto your nails and if they are really discoloured, mix in a drop or three of lemon juice and rub onto your nails.
Mouthwash and vinegar
Mix a drop of mouthwash with a drop of vinegar and rub it into your nails.
Mix a drop of mouthwash with a drop of vinegar and rub it into your nails.