@PollyThePixie I have a few regular purchasers who I chat with (entirely within the chat function of the website, so no personal details exchanged). Some will want items worn for specific purposes (e.g. the gym, masturbating, urinating). Others get off on buying things I've worn to work (teacher fetishists). Length of wear can impact on things. These are the items which sell for more.
That being said, I do a monthly shop for generic lacy pants in various styles and colours which I wear for a day as standard, but bag and sell instead of put in the laundry hamper. They tick over quite nicely with no interaction whatsoever with the purchaser. I've also sold a few pairs of my usual M&S mid rise cotton jobbies which I would never have dreamed of posting, but have been requested. I even sold a pair of Morrisons full briefs that I still had kicking about from the postpartum days with the DC which had a hole in, and I really should have binned already, but they were comfortable. I was sad to see them go, but they sold for several times what I purchased the original multi pack for😂
You don't have to offer more than you're comfortable with. The site keep out of it, just take their cut. It's up to you entirely how involved/interactive you are. If you're considering it, look at a few sites, you'll see the vast range of things people offer, and decide what could work for you. There are no contracts involved, so if you decide it's not for you, you're out without issue.