MY ES300 has been leaking engine oil, I'd say about 30 +/- drops or so each day

Depends what is leaking as to how much the repair will be. If it's the oil drain plug gasket, not a big deal. $20 - $30 to fix. If it's the oil pan seal, $400 - $600. Worse case, it's the rear main seal. Then you at the $1,000 point. Those would be the 3 main sources of oil that is dripping on the ground.