I'm a fan of Rebecca Minkoff so if I were to get one right now and had $400 available, it would probably be the Love Jumbo Shoulder Bag or the Mini Perry Satchel.
I just got a mint condition second-hand Chloe Ethel for that price on eBay. I've been watching them (and the selling rate) for probably 3-4 years and the prices are much more manageable now.