How to estimate property management costs in a 4-plex

[Greg Gibbons]

How do I estimate how much property management costs would be?  I want to buy a 4-plex in Louisville, KY.  Initially, I plan to live in it, so I won't have PM costs, but after a year or two, I see myself moving out, so I want to budget for the costs. Make sense?

In a similar question, I am assuming it makes sense to do my analysis based on renting all 4 units?  While i am living there, the rent will be lower, but will go up when I move out and rent it.  (the rent I don't pay, I plan to save anyway - I would pretend I am paying rent, but actually pay it to my savings account)

Thanks!