Can I take a pre-workout supplement before workouts, and protein after workouts?
As Helgi says..... It's your money. But "supplements" are unnecessary and likely a waste of that money. The whole supplement industry is highly suspect and almost completely unregulated.
As to protein.... Yes, protein is needed to provide the material for repair and muscle growth. But you need carbohydrate as well, as that's the "fuel" your muscles use.
Mainly, you need a well-balanced diet skewed a little more to protein intake if you are "body-building".
A good post-workout "recovery" item is a pint or so of chocolate milk.