How to Sell Roblox Created Items
Right now only an account with a membership can participate in private selling. Additionally, as with trading, only items marked as Limited or Limited U are able to be sold. If an item is Limited or Limited U, there will be an icon declaring it as such underneath the item's picture when viewing its details page or when browsing the catalog.
To sell an item that meets the above requirements, first go to its details page. Once there, click the three dots above the box that contains the price and Buy Now buttons. Then select Sell in the menu that displays. You will then be given a box that lets you set your price.
Note: Please be very careful during the pricing process. If you set the wrong price and it sells (a cheap price can cause the item to sell almost immediately), Roblox will not be able to reverse the transaction.
How to Create and Sell Your Own Items
If you would like to create pants, a shirt or a t-shirt from scratch, you can sell those as well. For steps on how to create and sell items, check out the Developer Hub for more information.