What To Wear... My Brother's Wedding

My brother is getting married in less than a month and I need to find something quick. I'm afraid to by anything because by the time the wedding comes I'll be 9 months pregnant. I feel like a big growth spurt is going to happen any day now.

I'd really like to go low key and not spend a fortune. I'd really like to avoid anything over $50. Does that sound cheap?!?! Sorry, I'm not sorry. I just can't see myself spending a fortune on a dress I'll never wear again!

I've seen a bunch of really cute dresses on ASOS but their largest size in most dresses are 14. I'm worried they may not fit! Before the bump I was a 14 especially on top so I'm concerned. I may order a couple of dresses because they have no shipping both ways. Has anyone ordered from them? Do the sizes run true?

Here are just a few that I'm loving:

source

Which one do you like?
Does anyone have any other suggestions on places to shop?