A macro lens works well, soemthing with a shorter focal length so the camera doens;t have to be too far away. This is when the 50mm macro lenses are popular.
Lighting and backdrop are more important than the camera though, because even a bad camera with bad auto focus and relative poor image quality will still easily produce excellent results since everything is so controlled and you can manually focus.. IN that respect an older second hand DSLR is plenty adequate. Money should be spent on fixed lighting, flashes, backdrops, a really good tripod and head, preferably a macro-focus rails, and a remote trigger. For many objects you might need to focus stack.
It'll take some practice to get good results, e.g. avoiding heavy shadows, creases/joins in backdrop, adequate depth of focus , but once you have mastered the basics then it will be quick and easy to repeat for hundreds of product shots.
