buy the parts to make your own try using a halogen lamp as the heating element, a jam jar as the chamber (upsidedown), mount it together in a wooden base with simple electrics to power lamp.
i bought one off ebay which was homemade but made very well and worked very well you can make one using the above materials an some others quite cheaply otherwise unless you got one secondhand youd have trouble getting a decent one for that price
try to find a site that will show u how to make one
i found the halogen lamp heating air that passes thru the green to be the most cost effect way