"Safe" amount of money before purchasing

[Chris Chesser]

What is (generally speaking) a "safe" amount of cash to have set aside for expenses before entering into a first deal? In my area I can find 3-4 unit properties around $120K (smaller town) so, obviously on an FHA loan 3.5% would be $4,200 + any closing costs. I'm trying to figure out a timeline for myself, on a meager 38K income, to get the ball rolling for buy & hold rentals but don't want to hamstring myself when the inevitable unforeseen expenses occur. I intend to house hack the future property. Any help is appreciated!