The best I've seen has been 25% off all regularly priced items (that was a couple months ago). June 21-July 6 BB will have a huge sale event.
3 for $159 regular dress shirts and regular sport shirts
2 for $159 luxury dress shirts and country club sport shirts
3 for $119 golden fleece polos
2 for $119 chinos
40% off ties, sweaters, jackets
30% off 1818 and brookscool suits, blazers, sportscoat, dress trousers
25% off casual pants, shorts, cordovan shoes, other footwear
50% off men's accessories, peal&co footwear