I'm plus size and petite. If you've ever seen my blog before, you're thinking DUH. Where I live, there are virtually no stores that carry plus size lines. The Kmart doesn't have the new plus size line. The Walmart has some stuff, but very few petite items with lots of "old lady" styles. There was a Lane Bryant; it left. An hour away, there's an Avenue (my favorite store!) but I only go to that town every third month or so. Thrift stores? Try a rack of old lady clothes squished next to the maternity clothes (they are NOT the same, people). So. If I want cute clothes, professional clothes, clothes that are awesome and wearable...I have to shop online. I have four places I shop: OneStopPlus, Avenue, Fashion To Figure, and Simply Be.
Avenue (favorite store!) has a combined website with Jessica London, and caters to the cool thirty-something crowd. They have professional clothes, weekend clothes, dressy stuff, basically everything you need, and they give you coupons every week for something if you're on the mailing list. Shipping here is expensive.
OneStopPlus is a website that pulls together stuff from all sorts of plus size clothing companies: Avenue, Jessica London, Roaman's, Ellos, Taillissime, just tons of them. They give you mailing list coupons as well. About half of the stuff is frumpy old lady shuffleboard clothes, but the other half is adorable. So you just have to look. They also have home stuff, men's clothes, and a few new expensive brands - IGIGI and 148 Lafayette New York, Kiyonna, Svoboda, etc. If you join, shipping is $3.
Fashion To Figure is a website that evolved from a NY branch of stores. It's a clothing line similar to Torrid, but less teenage, and more twenty-something. It only goes up to a 3x (supposedly a 22/24, but they run small, so check the size chart). They have coupons (seeing a theme?) and some awful cute tunics. If you order over $75, it's free shipping.
Simply Be is a site that started in Britain but now has a US site as well. They are the most expensive on the list, and I've only ordered from them twice. But the things I have (a cardigan and a dress) are gorgeous! Well made, beautiful. They do run sales and coupons, so I would wait and stock up. The Joe Browns line is fantastic. At the moment, all shipping and returns are free.