A 2014 Tesla Model S 60 battery upgrade from 60kWh to 75kWh costs about $10,000. In 2017, Tesla discontinued the 60kWh battery in the Tesla Model S, as most consumers opted for the larger 75kWh battery. At the point of purchase, a battery upgrade costs roughly $6,500, but Tesla offered a special $2,000 pricing to upgrade for a short period.
To swap a 60kWh battery for an 85kWh pack today, the price would be around $18,000.
Long story short, the cost of a battery upgrade for a 2014 Tesla Model S 60 depends on the battery you choose to upgrade to, with larger batteries having a higher price.