Most of the recent Star trek eBooks from Amazon are $7.59. The first two Cold Equations eBooks are $5.99 which is still more expensive then BooksOnBoard's price of $5.59. So, if you were to buy all three Cold Equations eBooks from Amazon, you would be overpaying by $2.98 given that at BOB with Google Checkout the final price is $5.53 each.
Given that you feel that stripping DRM is too time consuming (when it's no more time consuming then dropping an eBook into Calibre once properly setup), you must really like DRM. Do you feel that you will always have a Kindle and not some other reader that handles ePub? Do you want all your eBooks locked behind Amazon's walled garden? Personally, I don't want my eBooks locked to any one platform/format. I want them to be free so I can do with them as I want/need.
Sometimes I make changes to the eBooks to suit how I prefer them to be. I can't do that if I have them stuck behind a wall of DRM.
But anyway, feel free to stick with the DRM and higher prices. Having done the DRM removal and the conversion process, I can honestly say that the extra time is very minimal.