Piecework n. Work done by the piece or job; work paid for at a rate based on the amount of work done, rather than on the time employed. "The reaping was piecework, at so much per acre."
... listless voice. "She come by it from them uppidy folks o' her pa's. I've saw her when she wasn't much more 'n hair an' eyes, times her pa was laid up with the misery in his chest, an' me with nothin' but piecework... — Slippy McGee, Sometimes Known as the Butterfly Man • Marie Conway Oemler