USPSExpressFlatRateEnvelope $1.00,

[jtbi_77]

what can be shipped via the  USPSExpressFlatRateEnvelope $1.00,     

[comics-scifi-collectibles]

@jtbi_77   I am not sure where you are getting a price of $1 for a flat rate express envelope

The shipping cost is 24.90

  What are you trying to ship?   

Are you asking about eBay Standard Envelope?   It's a special eBay shipping program.  You can see what items qualify here:  https://www.ebay.com/sellercenter/shipping/ebay-labels-services/ebay-domestic-shipping-services/ebay...

[jtbi_77]

The flat rate envelope option is gone but there is:

Flat: USPSPriorityFlatRateEnvelope $1.00,  

and

Flat: USPSExpressFlatRateEnvelope $1.00, 1 business day

I copied and pasted these options from the drop window when opting for what shipping service you want to use to sell.

I've read that some people have claimed that even though it says $1.00 they end up being charged, or the customer, $3.50 so I'm pretty wary

I used the ESE for quite a while and then it disappeared many months ago.  Sucks