Buying an older model, MBP is it worth it?

Im in need of a macbook to use for video editing on location. However i can barely afford a 15"inch Macbook as they are so damn expensive. I was looking at some older ones and saw this one from early 07 for about a third of the cost of a new one.

Is it a good idea to buy an old macbook, considering cost/performance and that i will be buying a new one as soon as i can afford it, and this is just to bridge the gap for a few months.