Why can't you go shopping yourself? I am genuinely curious, not being sarcastic. Costco is typically stuff that you buy once a month if that; can you not even spare an hour or two once a month to go shopping?
If you use Instacart app to order items from Costco the price is actually different. I guess using Costco.com I have my membership benefit.
What is the meaning you are trying to convey here? Genuinely confused by this sentence.
I think "I can care less" is meant to mean "I can care less than most people do, because it doesn't matter to me".
Is this supposed to a be rhetorical question or are you genuinely unable to use Google to discover simple facts?