when buying jeans, i look for the look, comfort, and fit. i think the most i'd spend is $100. my cheapest pair of jeans are a pair of dkny's i found on the clearance rack for a whole $14. my most expensive pair are buffalo's that i picked up at loehmann's for $60.
my ex-gf loved jeans. her closet had around 50 pairs, and they're all $100-300 each.