The 2021 Volvo S90 is available as a 4-door, 5-seat sedan. Starting at $51,550, the 2021 Volvo S90 Momentum is powered by a 2.0L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 32-mpg on the highway. The top of the line 2021 Volvo S90 Inscription, priced at $54,650, is powered by a 2.0L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 32-mpg on the highway.