Source - I rented out half of my duplex for ~ 5 years. I'm not sure how it would work with renting out a single shared dwelling space, but might be worth investigating.

Since you have a roommate/tenant, you could possibly take advantage of real estate rental deductions, if you were to report that income using Schedule SE (might be a different name now). You'd have to pay taxes on the rental income, but you get to deduct a proportional amount of acquisition expenses (closing costs + purchase price, any capital improvements to the structure) on a depreciation schedule, and can also deduct the proportional amount of more regular expenses (property tax, insurance, mortgage interest (I think), landscaping/trash removal etc). The "proportional" part is usually set as the proportion of square footage that is rented out.

If you go this route, a CPA is a godsend for preparing the depreciation schedule for the property.