Amazon’s reasonably-priced entry into the tablet market, the Kindle Fire, had a hot start selling an estimated 2 million units in its first two weeks. It later topped Amazon’s own lists of the top-selling devices during the holiday season.

But after is was revealed that since the Kindle Fire costs just a little over $200 to make and sells for only $199, Amazon is actually losing a few bucks on each sale ($2 to $3), some began to wonder about the profitability of the tablet. Could Amazon’s long-term strategy of recouping these losses with e-book, app, and video sales turn the Fire into a highly profitable venture?

According to RBC Capital analyst Ross Sandler, Amazon’s Kindle Fire is probably more profitable than you think.

Here’s what he had to say in an research note:

Our assumption is that AMZN could sell 3-4 million Kindle Fire units in Q4, and that those units are accretive to company-average operating margin within the first six months of ownership. Our analysis assigns a cumulative lifetime operating income per unit of $136, with a cumulative operating margin of over 20%. We believe these insights could ease some investor concerns around operating margin compression per Kindle Fire unit in 2012, which bodes well for Amazon shares.

It appears as though the apps, e-books and even Amazon Prime membership sales will work generate a not-to-shabby profit for Amazon.

Their research found that over 80% of Kindle Fire users used it to purchase e-books, and that’s one of the first things they do with the device. 58% of users reported buying at least three e-books within 15-60 days of purchase. If each user buys 5 e-books per quarter at $10 a piece (estimates), that would be $15 in e-book revenue each quarter.

As far as apps go, 66% said that they had bought at least one app and 41% bought at least three. If you assume three app purchases each quarter, you can expect $9 in ad revenue per user per quarter.

After you tack on things like videos, subscriptions, and the Amazon.com purchase every now and then (51% increased those purchases because of owning a Fire), you can see how the Kindle Fire is projected to be proiftable during its lifetime.