I came to the belief that a healthy nutrition avoiding processed food, hormone laden meat and dairy products is much more important then vitamins and supplements for overall health and PE.
If you have a good nutrition then supplements and vitamins are in my opinion more a psychological aid - so go for cheap quality I would say.
Save your money for things which work, thats not supplements but drugs and a positive mindset.
Drugs which work are Cialis, Viagra for a better erection and bloodflow to the private member (good for the mindset too), and the only working libido enhancer known to me - GHB/GBL (provides a nice flaccid all the time, the permanent hornyness can be distracting though. Sadly GHB is illegal everywhere, but GBL is still legal in big parts of Europe, not intended for human consumption but nevertheless, electronics grade beats pharmaceutical grade every day anyways…).
The second makes of course only sense if you are low on libido - if you are already a horny bastard it makes no sense and GHB/GBL is a serious drug, be warned.
I wish I had spent my money on better food, a low sodium diet and something hedonistic instead of vitamins and stuff.
But if you live already healthy and if you have money to burn and you dont want to send the money to me for unknown reasons (I would coach and motivate you of course in return - I can do this, I studied psychology!) then buy expensive vitamins. Many people are motivated by spending money - the more, the more motivation. So strange as it sounds so common it is.