No, no and NOO!
but let me start differently
find you a motor..uhm that'll be your first
"No" I'm afraid,
a golf cart motor will likely work but since you want it to be cheap you need to find one on your own. (locally, used..cheap)
It will not be easy (and that'd be the second
"No")
you will have to source either the complete golf cart and reuse all it's electronics to reuse those, or will have to find other matching parts, even the first option is not exactly an easy task, since you need to either find the schematics or draw them while disassembly.
the 'base' is crap.. you won't add a motor to a pedal kart, especially not if your target is above 10mph, so that is the last
"No".
Do not even try, the wheels are not up for the task, the seat has nearly no support, the brake will not hold up, you do not have enough room to fit everything in and last but not least,
the weight will simply smash the frame under your butt on the very first bump you run over.
Forget about it.
'sid
