Just turn sending via Royal Mail off so you don't have to pay for postage!
there are also posting options for you to choose your currier in settings and then vinted determins the price depending on you chosen currier depending on your parcel size
I used to sell a lot on there but found that personally, Mercari has been the best and I've been using that for 10 years and Vinted for maybe 8ish and haven't had a sale on there in almost 2 years and I upload things all the time. It doesn't hurt to try it out though! But Mercari is definitely my go to! Vinted seems a little better when it comes to setting up the postage stuff but I never really have any issues with it once choosing the size of the package. 🙂
Vinted sets the postage automatically when you select the size of the parcel, small medium or large, you don’t have to worry about it x