Anyone who commonly crafts items and sells them on flea for a profit will most likely find this useful.
You can use ChatGPT with the following prompt to find the fee of a sale on flea
———-
Solve VO × Ti × 4PO × Q + VR × Tr × 4PR × Q
VO = [Price]
Ti = 0.035
PO is a modifier calculated as log10(VR / VO)
PR is a modifier calculated as log10(VR / VO)
Q = [Quantity]
VR = [Quantity × Price]
Tr = 0.06
———-
[Price] is the value of just 1 item
[Quantity] is the amount of items you are selling
[Quantity × Price] is simply [Quantity] multiplied by [Price]
Anything in square brackets you will have to fill in yourself for obvious reasons.
After doing that you will be left with the total price minus the fee.
Source: https://www.reddit.com/r/EscapefromTarkov/comments/11taa57/flea_market_fee/