Boyle uses low budget guerilla film techniques for feature films sometimes. 28 Days was the first feature shot on consumer tape cameras, Canon X1 I think, and they compensated by using a lot of them at once.

Most expensive scene was an empty bridge in London at 5:30AM, IIRC, and they only had a few minutes to pull it off. Lots of cheap cameras gives you options, if you can work with resolution and lens and colourspace issues.