Now, there are a few loan products that will not have monthly PMI such as VA loans and Rural Development loans, no matter what the down payment is.
Also, some little known ideas are if you put 10% down, a 15-yr term FHA Loan will not have monthly PMI. There is also an option for 10% down on a conventional loan without PMI as well.
Lastly, there are also 1st and 2nd mortgage combinations that will not carry PMI (1st mortgage usually with a 2nd lien Home Equity Line) that will avoid PMI, but you will still need 15% down.
In order to avoid PMI you must pay 20% down on the purchase price or you can have it removed by the lender
after you reach that amount on your mortgage. Be sure to contact your lender for specific answers to your situation.
I hope this helps!