What are you going to primarily shoot? Though you could use a zoom lens a good prime lens is most often used for movies. Examples of prime lenses include the 24mm, 35mm, 40mm, 50mm, and 85mm. It all depends on how wide of a shot you need.
Lens Focal Length*
Terminology
Typical Photography
Less than 21 mm Extreme Wide Angle Architecture
21-35 mm Wide Angle Landscape
35-70 mm Normal Street & Documentary
70-135 mm Medium Telephoto Portraiture
135-300+ mm Telephoto Sports, Bird & Wildlife
Source:
http
/www.cambridgeincolour.com/tutorials/camera-lenses.htm
The best used price I could find for one (Canon EOS 70D) is just under $900 but that was a brief search.