Original Post
[Market] How do I sell items for TC and ST?
I see some people are able to sell items for TC, ST or a combination of both.

How will I be able to sell an item for ST?
ST is an untradeable commodity and therefore, you cannot sell items for ST.

You can however, buy items on the ToriShop with ST.
I'd assume the initial question was regarding certain listings on Market that have TC + ST prices.
That's a feature available to Premium shop owners: they can sell you items even if you don't have a high enough belt for it - in that case you pay an additional fee in Shiai Tokens depending on your Qi. That fee, however, is paid to the system so the seller doesn't receive it - so essentially you can buy items for TC + ST, but you cannot sell them for ST.