I've found that sometimes when posting questions on the internet, and you want to avoid some sticky bit of your question, just straight up lying to smooth the backstory can work, as long as you're sure what you're lying about doesn't matter when it comes to the discussion.

So you could have said you were gifted the CPU by a friend so you're stuck with it (even if you don't have it), or a friend can sell it to you for cheap (maybe the same price of your discount), and then go from there.

Obviously you shouldn't do this in-person, but this is good for stack overflow or random internet conversations.