A Question for Americans, Re: Insulin costs

I've just been informed that insulin is cheap at Walmarts https://www.walmart.com/ip/Relion-Novo-R-Flexpn/475352650

So, for those with experience of this, * these will work in pumps? * This is just "insulin"? * You can inject it from the pen or you can put it into a pump vial ??

Honestly I'm shocked at this, so if people have experience, can you inform this poorly informed foreigner?

Thanks