Help to understand cash flow

[Jasmine Claye]

what is considered a good return on a rental investment?

I am considering a deal but not sure if the numbers are decent to even bother.

Purchase price: $50K

Yearly rental income: 15K

Yearly HOA: $3K (all landscaping, HVAC & exterior maintenance included)

Yearly Taxes: $700

Yearly Insurance: $450

Yearly PI: $3960

Yearly Avg expenses: $1.5K.

Not sure how to calculate the vacancy.

Rental Income - HOA - Taxes - Insurance - PI - Expenses - Vacany Allowance? = 5390

5390/12 = 450 per mnth CF

What am I leaving out?

I plan on using 2 loans to purchase, as one loan will be an equity loan from another property, which I will use as a down payment.

What is a good percentage for determining cash on cash investment?