Huge Sighhhhhhhhhhhhhhhhhhhhhhhhh...
Everyone always wants to get away cheap on sound.
"I think I'll blow every single penny I have on a new camera!"
"Man, the sound in this camera really,
really sucks!"
"Hey, can someone save my ass and recommend something that will give me Hollywood sound for $1.99?"
It's an old familiar story.
Being a filmmaker is a lot more than pointing a camera at a couple of actors. Being a filmmaker means being aware of
every aspect of the filmmaking process. That includes capturing clean, solid dialog, and editing & processing sound during the post process. That means planning for it from the very beginning of the preproduction process. If that means going with a a lesser camera in order to capture solid sound you have to make that compromise.
SOUND IS HALF OF THE EXPERIENCE!
For anything resembling professional sound you will need to spend about $500 to $700. That will include a shotgun mic, a digital audio recorder and not much else.
we'll be careful not to be in too noisy areas
It doesn't work that way. The world is a very noisy place and the way microphones work only exagerates the noise. Only the right gear selection combined with skillful use will yield reasonably clean production sound.
So, now that I have all of that off of my chest... The Zoom H1 or H2, or Tascam DR-03, -07, PR-10 or similar device taped onto the end of a painters pole or hidden on the set near the talent is one option. If you have an audio input on your DSLR the MXL FR-304 shotgun with the Pearstone LMT100 adapter may do the job; remember to disable the AGC/ALC. That's as good as you're gonna do for $150 or less.