Coloured foils can be used to great effect to give your prints the wow factor. They work really well on packaging, stationery and folders. They're glossy and shiney and add a touch of luxury to your designs.
And remember you are not restricted to gold and silver. There are foils available in a wide range of colours.
If you are working to a budget, you need to consider how widely you use the foil on your print. For example, if you are using it on a letterhead, use it on the top or bottom of the sheet, but not both. If you use it for both, it will require 2 passes on the stamper - or a very wide roll of foil.
Email me if you need more detail on this.