I bet it’ll be the same as flu shots. It’s not like those are actually “free.” Someone is paying for them, whether it’s insurance, the hospital/clinic itself, or more typically a governmental agency (usually state or local). I’ve paid a small co-pay for a flu shot before, but most times it’s “free” because my insurance covers it.
Only time I’ve really paid for a vaccination was right before I travelled overseas. Needed a couple specialized immunizations and think that was like $75 total.