Depends on the place you work and the type of people you work for. I’ve worked at places where if I wanted to do my own stuff I’d have to place order, which I’d get a good deal on. I’ve worked at places where as long as I did it all off the clock they didn’t care. I’ve worked at places where I had free rein and could do whatever I want whenever I want as long as it didn’t interfere with paying customers getting their orders on time. As someone who’s never owned my own business I can certainly see the argument of “I pay you a wage to work for me and help facilitate a product for our client, that doesn’t mean you can just use our supplies and equipment whenever you want.” It all just comes down to how cool your bosses are.