Would i sell you my time machine?
Of course not... i only have one! And i need to leave the device in the hands of my staff, thus reducing the risk of clones. No need to sell the machine if i always maintain control of it. 

But the burden of the cost of operation? this becomes an area i'd like to improve, thus improving the time traveling quality while still providing supply and demand. 

This is why supporting my Patreon is the best investment you could make to assure you future parties. Assured happiness.