And will probably tick off the rental car company, as I suspect they are not easy to remove.
Most rental car companies now participate in toll-by-plate, and some charge very low fees to do so. For example, National/
Alamo/Enterprise charge $2 plus tolls on each day you pass through a toll-by-plate toll both, with a maximum of $6 across the entire rental period. $6 plus tolls for an entire vacation seems pretty reasonable to me.
Other companies do charge more. Here is a summary:
https://www.sunpass.com/rentalcar