If you win a major tournament (ie. megabucks or fiq) you will most likely be picked up by the manufacturer of the equipment you used to win it, at least free ball wise.
A close friend of mine was picked up by Brunswick for a year for winning the NABI National championships.
Another friend of mine was picked up by Storm for winning 2 sweepers in the eliminator a few years back.
A former teammate of mine was on Track's staff, he won a senior stop 10 years ago and hasn't done much else since, but they still send him free balls.
You have to keep competing and getting your face out there to keep your sponsorship.