When we lived up north we purchased custom blinds for our living, dining and bedroom windows through a mail-order company. They were very good quality and a bit cheaper than in-store purchased, if I recall. I don't recall the name of the company now. Back then you could also order wallpaper through them (if you had the lot#) as well. Just know you need to have the correct measurements and that you'll have to install them yourself but that should be fairly easy. The company may have been American Wallpaper and Blinds
As an aside to this...when we ordered our bedroom window...the company made a mistake and sent us two but wouldn't take the extra one back (it was no cost to us) as it had been a custom order. Not sure how that happened as each blind came from a different source!
