Supplements

Don't need BCAA's if you're drinking a shake. In fact you really don't even need the shake. It's just more calories added to your daily intake.
The fitness and diet industry advises so much "woo" to sell ideas and product. People in the general population don't need a post workout meal right after working out. It's "optimal" for about 1% of the general population and those people are usually hardcore athletes.
Stick to the multi, fish oil and melatonin (if you like), but if your diet is balanced and you're getting in enough protein, you don't need the others.
And most pre workout is hype too. If you have enough energy to work out, then there's no need for it. Lots of people take it................................because everyone else is in the gym.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition

Still so many people using BCAAs. They are worthless for people who consume adequate protein for the day (https://jissn.biomedcentral.com/articles/10.1186/s12970-016-0128-9). Literally just a waste of money. There isn't a single research study to prove that a multivitamin does anything for your health or performance whatsoever. If you are specifically deficient in a vitamin or mineral and the multi you take contains that then it may be of benefit but most people aren't clinically deficient in anything and if you are you can probably just supplement that particular deficiency rather than a multi. I don't personally consider protein shakes or bars supplements, I treat them as food because that's really all they are. If you enjoy the taste and/or they help you reach your protein goals then they are fine, if you'd prefer to hit protein by eating other things (meat, dairy, etc) then that's just as good.

As far as supplements of value, fish oil is good unless you happen to consume adequate omega 3's in your diet (most people do not). Vitamin D has research proven benefits even if you are not clinically deficient. The amount you want depends on your exposure to the sun and how much you get in your diet. That said, it's hard to overdose. I personally take 5000 units a day. Creatine is one of the most studied performance enhancing supplement in existence. It works but it doesn't work miracles. It's very cheap so it's certainly worth considering.

As for a preworkout, the number one ingredient that makes a difference in actual performance is caffeine. Beta alanine as well as citrulline malate are also proven to benefit in various ways. I make a preworkout consisting of 2-400mg caffeine, 3.5gm of beta alanine and 8gm of citrulline malate. I also mix my creatine in with it though it doesn't matter if you take creatine preworkout or not, I just do it for convenience. It's about 1 dollar per dose. How effective is it? There's no way to really know. I will say that I doubt my overall results would be dramatically different if I stopped taking any or all of the ingredients. I bet if you skipped out on the bcaas (worthless) and multi (probably worthless) you could make the preworkout with creatine for the same cost or you could just save money and take caffeine + creatine only. Again, none of this is necessary. Your diet and training will always account for the vast majority of your progress.