Tea Leaves Dress is one of the nicest dresses I've found. It's made of thin cotton & would be great to wear in the summer heat. The color is sepia brown, it features a bubble skirt, & would look great with pearls or any Victorian inspired jewelry.
The site reviews do mention a few negatives though including you have to walk carefully as the base of the skirt is small.
It's available for purchase at ModCloth.com for $64.99, a great deal for the bridesmaids who usually pay for their dresses.
The Pacific Wavelets Dress is vintage, glamorous, & inexpensive at only $52.99. It's only available in the blue you see in the image and it's made of 100% polyester so while it might not be the most breathable fabric the dress is certainly thin and would be great for summer wear.
It would be perfect for a beach wedding or anywhere where you can see beautiful blue water or Grecian sculptures.
Poetrie features a large selection of beautiful dresses that could be perfect for you special day.
This 'Prom Dress' is dark purple with satin lining featuring a small bow at the empire waist. It's made of a Nylon/Cotton mix with a Polyester lining.
Love Mitsy features a wide variety of dresses, all at low prices, in their Retro & Prom Dress sections that could work perfect for your outdoor wedding
Ava Dress is pure classic glamor and more and it's made for a bride who's not afraid of her bridesmaids standing out a little, er, a lot. The dress is made from luxurious shakira satin and features a faux wrap front and tulip skirt, back zipper, attached wrap belt, and gorgeous plunging neckline.
The shop, Pinup Girl Clothing, features a wide variety of beautiful, glamorous dresses for your bridesmaids, all at reasonable prices.
You can find the Ava Dress here for purchase at $108.
Joe Browns Perfect Tea Dress is available from Amazon.com along with quite a few other dresses available in my Amazon.com Store.
The floral print is perfect for a garden party and the thin polyester fabric make this dress a wonderful option.
It's available for purchase from Amazon.com for $66.
Other great online shops include Starlets & Harlets, Bettie Page Clothing, Retro Vintage Dresses, Daddy-O's, & Unique Vintage.