I have bought my PM for about 2 1/2 years from ainterol.eu after trying quite many brands which weren't working well or which were even totally fake.
Ainterol has also capsules, but I am using powder form for economy. They sell 250g bags for quite reasonable price of €24.95 plus postage.
I bought already several years ago a tiny scale with 1mg resolution from eBay. That helped me in "calibrating" a tiny measuring spoon which I'm for measuring my daily portions.
I'm taking about 1500mg/day, and one 250g bag lasts then about 5 1/2 months.
Note that PM powder doesn't have any strong or unpleasant taste. I mix it in yogurt which is a part of my breakfast. Very easy!
Hugs

Teddy