Shopping at Costco with Visa or MC for air mile bonus

[aperture]

My DW and I have been testing the waters with Airline rewards on Credit Cards.  We do not manufacture spending (yet), but we have been able to get some rewards by focusing our spending on a single credit card until we hit the $#,### by # months bonus threshold.  The place we have not been able to do this to date has been Costco.  They only accept Amex, debit cards or cash.

I am sure many of you already know this, but I only discovered yesterday on a search of the internet (took 2 seconds once I thought to research).  Costco sells "Costco Cash Cards" on their website that can be purchased with a Visa or MC and used at Costco stores.  They charge no shipping on these cards.  Genious.  I am hoping I can use the card for gasoline purchases too. 

Disclosure: I have no affiliation with Costco - as if.   -Ap

[Trudie]

My DW and I have been testing the waters with Airline rewards on Credit Cards.  We do not manufacture spending (yet), but we have been able to get some rewards by focusing our spending on a single credit card until we hit the $#,### by # months bonus threshold.  The place we have not been able to do this to date has been Costco.  They only accept Amex, debit cards or cash.

I am sure many of you already know this, but I only discovered yesterday on a search of the internet (took 2 seconds once I thought to research).  Costco sells "Costco Cash Cards" on their website that can be purchased with a Visa or MC and used at Costco stores.  They charge no shipping on these cards.  Genious.  I am hoping I can use the card for gasoline purchases too. 

Disclosure: I have no affiliation with Costco - as if.   -Ap

However, if you use a Costco Executive membership to buy the cash cards do you still get the percentage back on purchases plus the percentage on your Costco AMEX?  Seems like they would have something in place to prevent double-dipping.