Just saw this sitewide promo at Jeanswest - get $30 off when you spend $100+. The discount is automatically applied at checkout (no promo code needed) and is valid for a limited time only.
You'll be able to pick up two pair of jeans for about $110 (depending on the style you choose) in both the men's and the women's section.
More importantly, I've also heard that their maternity jeans are one of the best ones out there - they're comfy and good quality, ranging between $80 and $100. Actually the more expensive styles are just a cent short of a 100 bucks, but you can add a singlet for roughly $15 which is cheaper than any of the accessories at Jeanswest.
If you're trying to maximise your discount, check out sale items, such as the Lyocell maternity pants which are reduced to $59.99. Two of these would come to $89.98 after the discount, which is pretty decent for two pairs of maternity pants. Sizes available are: 8, 10, 12, 14, and 16.