Shipping is flat rate $7.50 unless it's over $75. 501s (price before code is $48, on sale or something) come out to $28.80 before shipping and tax. If I add two, it's about $30 apiece, which isn't bad.
I need a whole new wardrobe since I've lost 40lbs and 7" off my waist this year so I may go ahead and buy two pair. I literally have NO pants that fit my current waist size. None! I started wearing 32" waist about four months ago, and they're big now. If I shrink anymore, I'll be in freakin' kids' sizes (don't think I can without removing bone though).