$90 if you buy it, $80 if you ~rent~ ehm I mean "acquire" a temporary digital license.
my point being: due to the risks assumed (someone can click a button and rob the product from you), the rights lost (cannot exchange games with your cousin), and the general lack of consumer protections on digital rentals aka. licenses, I'm a firm believer that their price should be 20 to 50% of what a proper physical copy costs; starting from the fact that you cannot spend $80 on a game, enjoy it, then resell it for $60 or so as we all ought to be able to do in all cases no matter what.
Physical cartridges are just as temporary as digital copies; unfortunately. This is starting to be a big deal with the 3DS. Nintendo doesn't use ROM; the carts start degrading after a decade or two. The console tries to automatically correct any data integrity errors, but if you aren't using them on a semi-regular basis they'll eventually fail.
The 3DS homebrew community has built some tools to attempt to recover failing carts, but for long term ownership your best bet is digital copies that can be backed up. Homebrew that enables dumping carts is also good, but who knows when that'll happen for new consoles.
Nintendo is going to be doing digital game lending now so that's an interesting addition. I'll probably still buy physical since the first-party games hold their value so well.
my point being: due to the risks assumed (someone can click a button and rob the product from you), the rights lost (cannot exchange games with your cousin), and the general lack of consumer protections on digital rentals aka. licenses, I'm a firm believer that their price should be 20 to 50% of what a proper physical copy costs; starting from the fact that you cannot spend $80 on a game, enjoy it, then resell it for $60 or so as we all ought to be able to do in all cases no matter what.