Test bench? I mean back in the day you just hooked up a motherboard to a power supply with a video card and you have a test bench because all cpu's were the same socket.
Now, you need a motherboard for each socket cpu, which could be 10 different sockets depending on how old of a socket your supporting with your testing, so you would need a power supply, a motherboard of each socket you plan to test, and a video card for those mobo's/cpu's without integrated video.
How you think you can build a test bench for $45 I have no idea.