Are you sure you saw multi-family properties for $80,000 with a gross monthly income of $1,700 on our MLS?
If in fact, there were multi-family properties out there you can purchase for $80,000, with a gross monthly income of $1,700 and ready to rent, meaning no repairs needed, you will be facing fierce competition.
I don't mean to disappoint you, but I am active in this forum to provide Buyers and Sellers with the facts rather than just adding another "client" to my list.
Realistically speaking you may purchase a $110,000 duplex with a monthly gross income of $1,200 - $1,400, then again, there will be dozens of cash Buyers interested in a property with such return.
Regarding property taxes, assessments vary depending on the location, our County is divided into Unincorporated Miami Dade and a number of municipalities and villages.
Cost of insurance also depends on many factors, age of the property, electrical, plumbing, roof and water heater updates (aka 4 point inspection), location, etc and it is something you will need to quote individually with an insurance agent every time you consider the purchase of a property.