First, rent your microphones, you get what you pay for, and cheap microphones sound cheap. Better yet, hire a sound guy, who will know what he's doing. At the no budget level you can basically hire someone for the price of their gear rental, which is about 5% of the book value per day. To put that in perspective, I used to turn up to a shoot with $4-5000 worth of gear. My shotgun alone costs about $1500 to buy. If you do do it yourself - and that's more acceptable for documentary because nobody minds seeing a microphone - at least buy a book and do some practice in your spare time. You'd be amazed how noisy a refrigerator sounds when you're trying to record someone, or how loud a typical city street it.
But the reason I praise the Zoom above is because it's no larger than a typical camcorder. It fits in your pocket, won't attract attention on the street, and you can record up to 4 tracks with it. You won't always have a table for a laptop.
> you get what you pay for... cheap microphones sound cheap
That is certainly true. But a cheap sound today is a lot better than a cheap sound ten years ago, and it might be good enough for you. The only way to tell is to try it. On which note...
+1 on doing practice runs. Much more important than mic quality is placement and setting your levels properly. A cheap mic well placed will get you much better results than the best mic in a bad location.
First, rent your microphones, you get what you pay for, and cheap microphones sound cheap. Better yet, hire a sound guy, who will know what he's doing. At the no budget level you can basically hire someone for the price of their gear rental, which is about 5% of the book value per day. To put that in perspective, I used to turn up to a shoot with $4-5000 worth of gear. My shotgun alone costs about $1500 to buy. If you do do it yourself - and that's more acceptable for documentary because nobody minds seeing a microphone - at least buy a book and do some practice in your spare time. You'd be amazed how noisy a refrigerator sounds when you're trying to record someone, or how loud a typical city street it.
PLugging into your laptop - don't, the a/d converters are usually awful and you'll pick up a ton of electrical noise. Get something like this: http://us.focusrite.com/news/introducing-scarlett-2i4 (for a laptop) or http://us.focusrite.com/news/announcing-two-exciting-new-int... (for iPad). these are about $150 each and the quality is grreat. Whatever you buy, make sure it can output Phantom Power, a 48v power source for condenser microphones.
But the reason I praise the Zoom above is because it's no larger than a typical camcorder. It fits in your pocket, won't attract attention on the street, and you can record up to 4 tracks with it. You won't always have a table for a laptop.