The way I see it, there's two ways Apple can go with pricing their car. Either they undercut the competition like Tesla or they add a premium just all their other products.
One site I've seen suggests a price of $55,000 and I think somewhere around there would be a great spot for Apple to be in. Anything higher starts to price them out from the competition and would make it harder to convince people to go with them rather than buying from an established car brand.
Everything you need to know about Apple's plans for a self-driving or electric car (or automated driving system)
www.macworld.co.uk