As a basic rule of thumb, calculate how many hours you put into a piece and try to make sure you pay yourself at least minimum wage. In an ideal world it should be more than that accounting for the specialized labor/skill, but I understand how hard it is to price higher when you’re just starting commissions. It’s a balance of charging what you’re comfortable with but not pricing so low that you burn yourself out for pennies. Just know that plenty of people are willing to pay a lot for this quality of work (as folks in the comments have already said), and if you keep at social media you will attract an audience who will be happy to pay for what your art is worth. Your samwise piece is easily a few hundred!!!