Sending very small objects

Hello, it’s possible to sell very small items (stamps, coins, postcards, etc.) on Vinted, but the only shipping methods offered are parcels. There is no option for sending by regular mail. It’s complicated to make a parcel for a postcard, and it generates a lot of waste (cardboard, tape…). Do you have a miracle solution to fix this? Thank you for your help.

Since they removed the custom shipping fees, there’s no other way.

Then, personally, all my packaging is recycled, so it costs nothing.

The easiest thing is to make slightly thicker envelopes (with several layers of cardboard, for example)