BMW’s ReachNow car-sharing service this week announced a new flat-rate pricing plan that aims to make trips more affordable for users. Instead of being charged $0.41 each minute that the car is used and $0.30 for each minute parked, users in Portland, Seattle, and Brooklyn now have the option to pay a flat fee of $20 for trips up to one hour. BMW said this saves its users 17 percent from the per-minute rate. BMW kept its $50 flat rate option for trips up to 3 hours in all three cities, but also this week introduced a $80 flat rate option for up to 24 hours for users in Seattle and Portland — a 27 percent discount.