Take old glass bottles (i.e mayo bottles) and pour water resistant paint into them, put the lid back on and swivel the paint around in the bottle to cover the glass. Leave it to dry and you have colourful and cheap vases! Enamel works well!
Another tip is to take tin cans and to either leave them plain or stick a nice piece of paper on them to make a nice flower pot, pen holder or container!
Also you can get frames from the second hand store or from a discount store and spray paint them to look expensive! Also using wood varnish can give an interesting look!