Villain mostly has 2nd pair to the board or A high, so you want to bet something that gets called by 2nd pair. I would default to half pot or less, but it depends on what he thinks of you. If you want to bet $3, bet $2.8. A million supermarkets can't be wrong.
It's also a fun spot to overbet with your floats and nut hands because villains range is capped and he sets himself up for a guessing game on the river. You don't really want or need a bluffing range there at lolNL tho, so forget what I said.