Software is free like a puppy is free
Sofware is free like a puppy is free: the ongoing costs of ownership outweigh the initial price.
[or if the difference is useful, still don't fool yourself that it will cost nothing to own. Make sure you plan for the expense]
The money you save getting a "free" software product as compared to one you pay to buy or license should be almost negligible in only one part of the business case (you do a business case for a new tool right?). By the time you look at the benefits of a good tool, and the total cost of ownership of any tool, initial price ceases to matter as much.
Learning costs, initial setup, configuration/population, reporting, user training, administration, audit, data quality, support, hosting, maintenance, upgrading... All software will cost way more than the ticket price, just like a puppy.
[update: "free" software still has these technology-related costs, such as configuration, taxonomy design, data populaton, support services, infrastructure to run it on, upgrades to supporting systems, developing reports is a big one, and most of all integration. These are big numbers. And yet i think they are a third of your total costs if you truly take into account the impacts on processes, work procedures, skill sets, and user training. http://www.itskeptic.org/why-it-projects-fail-underspend
It would be an exaggeration to say licence costs become negligible in the face of all these costs, but i'd expect them to be more in the range of 5% to 20%. At that level other differences between products other than price become more important.]
More of the puppy analogy :
Shadow IT means "I'll get the puppy and IT will clean up the mess"
Any other suggestions for extending the puppy analogy?
Made in New Zealand 
