Decorate glass candle holders and sell for a profit.
45p for a holder with an embossed pattern - http://www.ikea.com/gb/en/catalog/products/20146073/
25p for a plain holder - http://www.ikea.com/gb/en/catalog/products/36418000/
75p for a candle in plain holder - http://www.ikea.com/gb/en/catalog/products/50209610/
Â£11 for 6 pots of glass paint - http://www.bakerross.co.uk/product.asp?pf_id=E812 - ebay may be cheaper
Get creative and make products to sell!
It may be worth practising on jam jars first.