My new batteries were about 250EUR/kWh - my 10KWh unit cost 2500 EUR - scaling it up to a decent used 5 year old EV price - you can have one for 15k with 60+ kWh batteries, so I'd say it's at a very similar price.
If you don't work from home it makes 0 sense either.
IMO we are long way from proving V2G usefulness. Micromanaging your car SOC every night to save $2 is nuts.