From my research, a lot of investors spend renovation money in such a strategic way that all their money of reno's is back with them in 24 months (Example below).

If you had a $3K per month marketing budget, how would you spend it to create a consistent stream of motivated seller leads month after month? 

But some sellers are more realistic.

They tell you nothing since you can't spend or save them. 

What are the realistic rehab project(s) possible with $1,000 to $5,000 budget in the Midwest? 

Also, I bought mine furnished and depending on where yours is located and what sort of demographic you want booking it (budget conscious, luxury, local emphasis, etc.) will have a huge impact on how you much you should plan to spend on furnishings and decor. 

Spend $10,000 in interest, get $2500 back. 

Plan to spend $350k over the next 2 years adding a new office, adding amenities and adding water meters to each unit.

If you like to self learn you don't need to spend much if anything. 

In truth I bet the cash flow is better outside the city, because I spend far less on turning a unit than those in town do, I suspect.