Either it was a simple testo cream (contaminated with nandro), then the costs are almost negligible, or a complex designer cocktail, then BTC would most likely be the (unofficial) organizer and payer.
Given how BTC reacted when she got caught, my money is on the latter (which would also explain her other high androgen levels).
Designer drug cocktail would explain her other high androgen levels.
An other ref to your posting re designer cocktail of drugs .