Another source for cheap film is Cangnan Guangming Printing Co (
http://www.aliexpress.com/store/205597). The price is comparable to Hobby King, but their smallest amount is one meter. It's also ok to mix films of different lengths and colours. I've bought from them a couple of times and the shipment has been made within two days. I'm not experienced enough to compare the film to any quality-brand, but it's been good enough for my modest use.
/Stefan