in m,y books? product#1
cost 4$
sales 6$

procuct #2
cost 5$
sales 7$

if i sell the second product with the sales price of the first(6$) as a promotion,how can i booked this transaction in my Financial statement?
should i book sales with 7$ minus cogs 5$minus promotion cost 1$
or book sales with 6$ cogs with (5$*.14) minus promotion