go to chah sultan (sultan ka kuh). u'll most definitely find used hub out there at a reasonable price. u'll have to bargain a lot.
waisay why do u want to change the complete hub. some serious problem or just wheel bearing problem?
i had wheel bearing problem on one of the rear wheels of my corolla 86. the mechanic told me to change the complete hub. second hand was available for Rs 800/-. but instead i insisted on changing the wheel bearing and hub seal. though it costed me almost the same but at least i had the surety of a new bearing.
changing the hub should be the last problem in case it itself is damaged.