The album does not cost 50$ per copy, nor is that a selling price of the album. Read the description on the Kickstarter page.
The album and bonus DVD, along with the free downloads of other albums (and some other stuff that OCR may include into the 50$ range as a way to thank the donors in that level) will not come to 50$, nor should you expect it to, because it is not a purchase of the album. It's a donation so that OCR can make as many physical copies of the album as needed for promotion, future distributions, etc., to promote the site, as well as creating a budget so the albums can be as professionally mastered and produced as possible. When someone donates 50$, they are rewarded with one of the printings of the album (as the Kickstarter mentioned, it will be available as a reward or gift at conventions and such - the donation mark is one of the cases of being a reward).
Again, this is not a purchase, it is a donation to a larger printing of the album for the sake of promotion for both the album and the site. I do believe it could have been made clearer in the kickstarter page that the money is also intended to support the site, as well, as this replaces the normal 'Support OCR Month' that normally helps keep this place afloat (there is mention of that on the page, but it's harder to find).
A donation of 50$ should not be a purchase of the album - the album will be distributed freely, so if you want the music feel free to download it when it becomes available. It won't have all the bells and whistles of a hard copy, but that's all it is in the end - bells and whistles. A donation of 50$ should be made if you want to support the costs of the album (which has been met, obviously) or if you want to support what this site is about (which can use the money - it's not a cheap place to upkeep and expand, when needed, with all the bandwidth used with free downloads). If you don't want to support the site, then people don't need to donate. It's clear as day that the drive has hit it's mark, so unless the hard copy of the album (as well as the other bonuses) are worth 50$ to you then the only reason to donate would be to further help the site out and possibly allow for better mastering and production options for the album.
I sent 50$ because I love the site and want to see it go for as long as possible. I hope people are donating for the same reason.