Patrick at Bingo Card Creator does this. If you search his blog ( http://www.kalzumeus.com/ http://www.kalzumeus.com/ ) you find the entries where he discusses

Patrick at Bingo Card Creator does this. If you search his blog ( http://www.kalzumeus.com/ http://www.kalzumeus.com/ ) you find the entries where he discusses it. For me it depends on what is the lifetime value for a customer. Very easy to determine if its a one time fee. And what is the lifetime expense of a customer. If the expenses (server cost, support, etc.) grow over time, then you are bound to lose money. If your application is one would only be used a few times, say wedding planning, or related to being pregnant, then I can see it. The big downside I see, is how do you handle upgrades. With a SaaS subscription model, they are continuously paying for the upgrades. With a web app with a one time fee, you would either have to give them the upgrade for free, force them to pay for the upgrade or maintain multiple versions. With desktop apps, it seems that you get a big boost in sales with an upgrade and I feel like you miss that with a one time fee for a web app.