I wonder why you can't find it in Karachi while I can easily find it in Pindi. 450 is okay only if the mirrors are SUPER QUALITY, plus you have to consider the SIZE of your side mirrors. Don't go for too big mirror, it'll confuse you and may actually reduce the rear view. I'm sorry I can't help you as I'm not in Karachi. And yes, this is a big problem if you don't have power side mirror option.
Yeah, that's it, and if you carefully see the picture, you can spot an EXTRA mirror on GMC Savana visible in that mirror because it is a BIGGG VAAAN :o