Why didn't Taihei just go to Japanese Costco to buy glasses?

I thought he loved bargains?

Also, after watching this video, I don't see how anyone would be willing to go to an eyeglasses store these days rather than an easy to return or refund company like Costco.

https://www.youtube.com/watch?v=gDdq2rIqAlM

Umaru's author seems to like shilling companies like Amazon though so he might have gotten paid to do this.