Buy a home and or office for myself or Invest duplex? Best Hack!?

[J Campbell]

I currently rent my home and a commercial office, both of which i assume i will need in future.

should i buy one or both before getting into REI?

a-buy a duplex and rent unit to have free or low rent?
b-buy a commercial office and rent unit to have free or low rent?
c-re invest and get more cash flow? 
d- other (ie sell business live on the beach)

like anyone, i have limited capital liquid which i want to keep liquid as much as possible .

whats the best strategy / hack for this?