Selling Test bitcoin

If you want larger amounts of testnet coins (0.1 or more), you still need to run a miner to get testnet coins and the amount of testnet coins is still limited to 21 million like maininet. So I can see why someone might want to pay a small amount for testnet coins just so they don’t have to wait for the mining process.

If no blocks are found on testnet in 20 minutes it will reset difficulty back to 1, which is the lowest difficulty making finding a block very easy.

So I suppose it depends on the patience of the person, if no patience then maybe you can find a buyer, but the difficulty reset is supposed to help keep the value at or near zero.