Indeed, Brian's reading me correctly.
You're headed for a simple, budget build. Not a performance build.
I suggest looking into cheap/free forklift motors which for your purposes will be nearly identical to the Warp11.
Since you're doing a budget build, you need to save as much as you can for the things you can't save money on (like batteries).
Controller-wise, pick up a Prius Gen 2 controller. Guys are finding them as cheap as $50. Then, soon as Damien get around to testing them, he's made a little control board to control DC motors with it.
he's got 10 in stock already. Probably cheap as chips, well under $100 is my guess. Maybe closer to $50. Cheapest DC motor control ever.