Yes I know, I know there are lots of different supplements you can take, but all I'm going to cover here is protein, and the ideal times during the day that you should be consuming it. Whether dieting down or bulking up, protein should be consumed with each meal of the day. It is important to keep a constant supply of amino acids in the blood, so ideally you should be aiming to eat a meal every 2-3 hours. Just make sure your macro nutrient breakdown of each meal is linked into your goal. The result - if you are cutting or aiming to lose weight, this will keep your metabolism high. If you are bulking and looking to put on muscle, you will be providing your body with a constant supply of calories to help you grow.
Outside of those meals is when a protein shake can really be useful. As it is in liquid form it is fairly easy for your body to process quickly. So, if the budget will allow it, when are the most essential times of the day to be having a shake?
First thing in the morning: As you (hopefully) have been sleeping for a good 7-8 hours, and therefore technically fasting, a fast absorbing whey protein drink first thing in the morning will put a halt to your body's catabolic state.
Pre workout: 20g before a workout will ensure that your body is saturated with amino acids ready to start the repair process. Failing that, try to consume 8g of EAA (essential amino acids).
Post workout: 30 - 40g whey (or 50/50 split whey/casein) post workout will enable your muscles to begin repairing.
Before bed: As you will not be eating again for another 7-8 hours, consuming 45g micellar casein right before bed will keep your body drip-fed with amino acids while you sleep. Micellar casein forms a gel in your gut, slowing down the absorption process and keeping your body in an anabolic state for longer.