Don't go with fake, nothing says cheap like fake flowers.
I would look around for someone that works out of their house. Try Criagsilst.
Doing it yourself is cheaper but list others said it get to be kind of hectic the day of the wedding.
Do you maybe have a crafty relative that could do that? Michaels has the basic supplies, use coupons and buy the supplies as they go on sale. From there if you can find a cheap source of flowers it's really not that hard to make the pieces you need it just takes a lot of time.
You might be able to find a wholesaler. Do you know anyone with their own business, some floral wholesalers are ok with that. For my ex MILs birthday I went to a floral wholesaler, I had a scrapbook business, they said just give them a copy of my business license. From there I got 100 red roses for 30.00. the were raw, meaning they needed a lot of TLC to take off the outside petals, fix the stems etc. I also went to the Salvation Army and bought every vase they had. We put the roses all over her apartment as a surprise. The whole thing cost me around 60.00 which is about what a Florist would charge for one dozen.
I got creative and was able to give her a wow surprise.
You can figure out something creative if you just think out of the box.
Lisa