Automotive: would this be a cheap fix?

I have a 97 buick and the problem is, my blinker won't work. the lever to initiate the blinking will stay down, and the light will stay lit in the front of the car but not the back, and it wont blink. sorry i'm very car illiterate. it's the drivers side blinker that is doing this. any idea what the problem could be? I have to manually flick the lever up and down for it to blink in the front, but i get nothing in the back.