@Peter Bui You may want to partner with your lender for an estimate of closing costs using the specifics of the property that you're interested in purchasing and the type of financing that you have secured, during that conversation you can ask how closing costs are calculated to see if the magic number of 3% makes sense in your situation
Each county is different. Most require property tax up front. Contact your escrow official.
Usually for the buyer this includes, property taxes, insurance, title company fees, and lender origination fees.
I’m not a huge fan of using percentages to estimate these costs. I’ve bought houses that cost half as much as others and the closing costs are the same.
I estimate 4-5k per closing assuming you’re using financing and it’s residential. Commercial would be higher