Depending on the design, you could either have it 3d printed or have it machined. Online services are available for either option (e.g. shapeways.com and emach

Depending on the design, you could either have it 3d printed or have it machined. Online services are available for either option (e.g. shapeways.com and emachineshop.com, respectively), or you could find a local job shop to do either. The online services require you to provide them with prepared CAD files. A local job shop would be able to work with you on the CAD files if you don't have them already. Another option would be to try printing it at a local hackerspace (e.g. dallasmakerspace.org). Feel free to contact me if you want some more direction. I haven't prototyped consumer products, but I do spend a lot of time building one-off devices for physics research. You're right not to want to order your own 3d printer for this. The hobbyist grade ones still aren't plug and play, so you'd burn too much time getting it working.