Purchase: 150k with 30k down.
Renovate: 30k( get a construction loan so you don't pay anything...)
Sold: 220k in 5 months.
Expenses: fees, taxes, interest... 20k.
The other 7 month: in cash position. It is hard to always have profitable flipping opportunities worth doing.
However, if you do it all cash, then you got roughly 20-25k on 200k working capital.