If it’s a simple product then like bepster mentioned, find a freelancer/student/professional whose style you like; maybe they already show a product very similar to yours on their portfolio so the job should be fairly straightforward.
However, it all depends on the types of shots you want, materials, environments and quality of the 3D model. I love it when people say, you just hit the render button and i’s done. Nobody talks about the hours/days cleaning up the 3D models, setting up the scenes, tweaking the materials, lighting, cameras, etc.
Cost will probably be all over the place depending on what you need and who you contact.