Another design of a "why not do it properly, if it can't be made improperly" type.
For "PWMing" a motor, where there is not a requirement for 100% duty cycle ratio (which rarely is really required), use just a couple of cheap half-bridge drivers, such as IRS2001 or any other from the thousands of similar ones. Done.
If you that much need to go even cheaper, then by using a couple of discrete transistors, make the bootstrap driver. 2 transistors minimum per mosfet required to do all the heavy-lifting from 3V MCU up to the high/low side gate.
//EDIT: Typos.