I got a really cute frock at a random store in London about two months before our registry office wedding. I decided not to purposefully look (I've been a bridesmaid and seen the bride and other bridesmaids in tears trying on dressing - and not good tears) so I just casually popped in to shops when I got here. When I found it, I knew.
My dress was a knee-length pleated black dress with white pinstripes and little decorative bits and a white lace back. The brand is Closet and they've got lots of cute dresses at Debenhams and other shops now. I love my dress. And it was less than £50. And it has pockets! And it's machine washable. I can totally wear it somewhere else and it was classy for our wedding but funky so it's memorable and definitely unique.
If you're not having a big wedding, wear what's comfy and what you want. If you can wear it again, you can still show it off to friends and family back home. If you're getting married in November, maybe it could double as a Christmas outfit (I'm not suggesting Santas and reindeer... Just appropriate for the weather). I'm sure you'll find something.
What are you doing for shoes? I debated between boots and flat (I'm not a heel person) but went for some awesome red flat I stumbled upon. I made DH get a tie that matched my (clearance!) shoes but that was really matchy-matchy for us.