When I first started out in 2008, M2 was much more expensive than it is now.
The last time i placed an order I paid 495 british pounds for 50 vials, but I still see people asking 30 pound for just one vial.
My experience is not that the cheaper ones are worse or give more side effects, I think claiming you have better products is mostly a way of promoting something many sellers have purchased elsewhere. So I thought it was time for a prize-quality discussion ( and I'm not looking to order anytime soon but in a few months from now)