ebags has good prices. Also check steepandcheap.com. You have to check it often but they do have a lot of rolling luggage from good vendors like North Face. Most are <$100, <$200 for the bigger ones.
I used to travel 100K/year. I learned very early that if you want luggage to last, you get what you pay for. I used to swear by TravelPro and Tumi, but they're $$$. You find others now that are much cheaper. I also used to swear by hard-sided, but now that airlines are so strict on weight, I prefer softside and use the weight for my contents and not the luggage itself. Expandable is also good, so you can have extra space for souvenirs when you come home.
I like the roll on/carry ons that have the zippered backpack that attach. Some of those fit in overhead bins. PLUS, if you're a guy, you can 'cheat' the single carry on rule by connecting them together when you go through gates and the detach them to fit in the under/overhead storage.
