Quick overview of how these things work. (Score 1)

The cost of Microsoft software depends largely on the state where you work. For example in Texas there is the Texas Department of Informational Resources that negotiates pricing for 99% of Gov/Ed. They form contracts and have authorized distributors that sell at that price. Also I would become more familiar with how your university is structured. Some are divided into multiple schools (CS School, Business Management School) and each has its own rules and purchasing. Your best bet is to start with a small student facing project like a lab that uses 100% open source and possibly take your time to give occasional tutorials on how to use stuff there. Or possibly start a NEW project using open source teaching products like Moodle, dont try and replace an existing one. Once you have that small win you can use it as leverage to prove that going 100% open source is possible. Also dont expect to change the school overnight. Also be sure to be realistic with your expectations. You will almost never ever be able to get a company to drop Microsoft Exchange/Outlook or Windows Server if they use it currently. Find another area to leverage open source and leave those alone.