My organization, we currently have Office 365 email only, and we are trying to get a free Teams tier account set up. Is that possible without having to create an entirely new tenant for Office 365? There are only like six or so of us, plus anyone from outside that we plan to add, though our group is way below the 300 member threshold not to qualify for this. Any assistance would be much appreciated. Thanks.
Unfortunately No. While trying to sign-in for Team's free tier with your existing Office 365 email address, it will highlight that your org is already using Office 365 services. Contact Admin to enable / assign Team license.
What licenses do you have on your Office 365 tenant?
If you have an Office 365 plan that doesn't include Teams, an option is the Microsoft Teams Commercial Cloud Trial offer. Check the Who is eligible section for applicability, for example, EDU and GOV customers aren't applicable but this offer provides a 1 year trial: