Switch download codes..

Hi All,
I just bought my youngest a switch for xmas. I'm don't want him to have to change carts etc as they'll get lost/damaged, and it looks like you can buy download codes to install direct to the switch. Are there any 3rd party sellers that do them a bit cheaper than Nintendo directly? Specifically I'm after Kirby and Mario (the switch came with Mario Kart).

I presume if I buy a physical cart it has to be in the switch when it's being used?

Cheers...

b0redom

Fanatical now do switch and 3DS download codes. I've not bought any personally, but have bought several PC games from them... and are generally cheap during sales. https://www.fanatical.com/en/nintendo

Greenman Gaming also does Nintendo, but think they're 3DS games.

Don't think either have any sales at the moment though.