For your budget of $100-125 Depending on where your from i suggest these two things.
Keyboard - Razer Arctosa Essential Gaming Keyboard $49.99
Mouse - Razer DeathAdder Essential Ergonomic Gaming Mouse $59.99
$110 all up. They are not the top of the line gaming products but they are in your range and still better than your average mouse and keyboard from Microsoft.
You could spend another $50-100 dollars and upgrade the mouse to have more buttons on it if you liked or the keyboard for more features, All up to you.
I myself just bought the black widow keyboard and razor naga mouse from razor. Good buys just a bit expensive though.