I'm building a PC in a couple of days with my friends. We all have similar builds but mine is the cheapest because I don't have an SSD. I didn't realize how big of a difference on made so, of course, I didn't order one. Now it's too late to order one and I don't know if I trust the ones from Walmart. I really want an SSD though and I want to build my computer with my friends so that we can all play together. I just want to get a 120gb one from Samsung (not the Pro version just the regular one). Can I add it in later and hwo will I put the OS on it?