Yes I would definitely recommend trying protein samples before committing to 5kg, I know True Protein tastes pretty damn good as I got a heap of samples from them and gave them good reviews, I really liked the taste of their protein and the taste might be worth the extra $$$ for me it certainly would in some cases.
Some people love the BN taste, I find it a bit too weak for my taste buds, but essentially they have a great pure, good quality product at a great price. Creatine is creatine, and has no taste, so you can quite happily order a kilo or three from BN it's only $19/kg last time I checked, I think I ordered two kilos last time and still have about half a kilo left as I stopped using all supplements. I will go through and use it up soon along with my left over proteins, I think I have about 3kg left here.
Mate they are not chemicals as such and they are only food, any excess will get discarded by your body, some people hype supplements up to steroid standard, when in reality they make so little difference they would not be worth their price at a ¼ of the cost, they do very little and most are totally unproven. I stopped using all supplements and it has not made any difference I could notice.
They are the 1% of your journey where training, diet and dedication make up the other 99%.