Who would rather pay $10,000 for a piece of software if they can have it free and be legitimate? Yes, free formulation software exists, and it works. The least cost linear-solution algorithm behind any feed formulation software is something quite simple and freely available. In fact, I created my first such formulation program using undergraduate knowledge in computers and programming language (Fortran, for those who remember!). But, you no longer need all that to create a simple formulation program. Today, the availability of spreadsheets enables anyone with some advanced knowledge in such software to prepare a simple formulation spreadsheet -- in fact, I continue to use mine after having worked with almost every single available product in the market.
A good search on the Internet reveals such spreadsheet-based feed formulation systems, some of which are absolutely free. Of course, they don’t come with the bells and whistles of a sophisticated product, but they will formulate a diet or two with the same accuracy and provide the same amount of output information as any other program.
Continuing the search, one also encounters free formulation software combined with ingredient and formula databases. If you need to have more than a handful of formulas, you definitely need these integrated databases. And, here is where most such software programs start to crash. As they try to become more user-friendly, they require a tremendous amount of product development, something that costs money and time -- both competing with the notion of being "free." So, the majority of such products tend to crash or become a headache -- at least all of those I have tested so far.
This is where an expensive piece of feed formulation software is worth its price (in most cases). But, before you buy, please ask for a demo. If there is not one available, and only a demonstration is offered, I would not buy. A feed formulation program is something you will spend hours with, so it is better to have it working with you.