Laptop CPU from EBAY???

Hello. I actually have done this before. Ebay I think is a pretty good and safe place to shop. That is how I got my laptop to be so good so cheap. I bought a used laptop with these specs:
CPU: i5-3210m
GPU: Nvidia GT 620m
RAM: 6GB
HDD: 1TB

I got this for $360 last October. After buying new parts and selling old ones, I am $600 into it, with these parts and I still have the original CPU and HDD from it to sell.
CPU: i7-3632QM
GPU: Nvidia GT 620m (Overclocked heavily)
RAM: 8GB low power, faster speed
HDD: 1TB+8GB HHSD.

I bought the CPU on Ebay for $144 and I feel fairly confident I have the most powerful laptop anyone could possibly buy for less than $700. So I think buying a CPU upgrade on Ebay is very good, but you need to make sure your laptop supports the CPU first. At least that it has the same socket.