I own a supplement company and I can tell you this. We have MSRPs with brands that we must abide by.
We also purchase in bulk to get better deals on pricing. Some brands I deal with have massive minimums and others do not.
And we have to make a profit but also be competitive.
I don't think people realize how expensive it can be to run a supp company. Lets say you have 100 products. Well you have to buy sometimes say 20 units of one item to get a deal on price. Multiply that by hundreds of products offered.
Were talking tens of thousands of dollars invested. Then you have to sit on products until they sell.
Manufacturers say someone like Blackstone labs for instance (chose the name at random). They are paying way way less to make those products then anyone knows and they sell to stores, customers, distributors. You name it. But they too have to put huge chunks of money up front for manufacturing, etc.
That's why those guys are driving Lamborghinis.
Small time retailers on the other hand, make a very average living. Or even small time brands. Theyre constantly re-investing money to stock items.
Strong is a bigger one and reputable so I'm sure they do pretty well financially.