Kyrra's friend wedding post J Crew, Nordstrom, Dillard, etc

Many of the major department stores and online shopping sites have wedding sections. If you feel more comfortable dealing with a company that is more established and where returns might be easier this might be a way to go for you.

J Crew I think is very pretty and well made stuff. A little pricy though. Here's a dress from their wedding section. It is in Dusty Shale, which seems to be blue green.

Lots of great bridesmaid alternatives on sale if you think you can make short dresses work with the tennis shoes. I think you can if you make the dresses almost sun dress looking like the one below, which is on sale for 70 bucks:

Nordstrom also has a Wedding Shop. Wedding dresses from 100 to 400 dollars mostly, a good variety of informal styles. This dress is on sale for 170 dollars. There are reviews too!

Also bridesmaid dresses, like this one in light green satin for 40 bucks.

Also try Dillards and Macys for reasonable alternatives. I thought this gown in cream for 180 dollars at Dillards was pretty

Finally, there is Ebay and Google. Just search for green wedding dress or green bridesmaid dress and you will get an amazing amount of dresses including for very cheap prices. I feel a little leary of the quality in some cases, but just pay very close attention to who you are buying from and make sure you are comfortable with them.
Hope this helps!