l wanna film the kelp forests for a movie whats a cheap under water video camera $60-$200

There is nothing in that price range for what u plan on doing. The cheapest u will manage is about $400 & that breaks down this way:
1/ $150 for a camera similar to a canon powershot. It takes both stills & has a good movie mode that also includes an underwater auto mode. You can put a 4 gig hcdc in it ( 40 bucks more) that will shoot at the cameras highest res on vid for about 38 minutes. It is decent quality vid, especially for the money.
2/ Canon makes their own underwater housing for these cameras.$250, but they do not take as much abuse as a housing from Ike Lite that also costs twice as much. Your choice here.

There r amphibious cameras out there from Sea&Sea, Sea Life & Bonica, but their shooting modes r limited. They range from $350-$500. You wo not have the same amount of control of the shoot with these cameras as u would from putting a decent land digital camera in a housing
You will also have to think about lighting, no matter which route u take. You will need a light set in that forest. The camera & housing u choose has to accommodate a tray to fix the lighting set to.

What u can do, if those prices have scared u off, is to hit a dive shop. Many will have shop rentals that u can have for a weekend for a reasonable price. You will have to put down a sizable deposit is all.