So, I need a formula to help me find out profitable ventures.
I am buying items for X and selling them for Y. However, there are fees involved.
Everytime I buy an item, an additional 1% of my money goes to a third party. Everytime I sell an item, 3.8% of my money earned goes to a third party.
I need to find out at what value of Y do I start to lose money.
For an example:
I buy an item for \$383.00. After the fee is applied, I am buying that item for \$386.83. If I sell it at 419.97, I'm selling it realistically for $404.01.
That's wonderful, I'm making $17.18 per unit sold.
However, how do I find out the lowest price I can sell that item for to keep a positive profit? I already found out that the lowest profitable sell price would be $402.12. However, I don't want to guess; I need a formula.
$\mathrm{Profit = Earning - Cost} = (1 - 3.8\%)Y - (1 + 1\%)X = 0.962Y - 1.01X$ , which has to be greater than $0$. So, $Y > \dfrac{1.01}{0.962}X$.