Alamo/Costco Q

[poppypetal]

I see Alamo offers a code for Costco Members - is there a generic code that is always valid, or do they offer different codes at different times?
We are looking at coming in September and would like a rental. I've heard they can get quite inexpensive from Alamo, if you search it out right.
But I want to make sure I understand how to do all of that

TIA