Double check your package weight and dimensions within the listing. Must be 3oz or less in the weight box - make sure 0 is input under lbs. I've accidentally put the 2 in the lbs box instead of the oz. box where it should have been inputted. I sell cards as well and use a fairly standard envelope exclusively. It doesn't default for me (?) , so I have to enter 7 x 4 x 1 on every listing. The 1/4" thickness allowed has to be round up to 1 in order for the system to accept it. If any of these settings are off and don't jive with the rules and regulations required by eBay for their Standard Envelope Rate, then the option for the rate itself will not even show up as a selection. Correct your weight, dimensions... and viola'... the rate automatically presents itself to be selected. Also, if your listing is an auction format and the final sales price winds up at $20.50, then the shipping rate will not show up as an option. The sales price must be $20 or less to qualify for the Standard Envelope Rate. Good luck selling!
