all i want is, to associate every expense that may belong to a particular sale that i made. for example, lets say i sold you a shirt for $100. you paid me $100 and now you received your shirt and you are happy......
now i have to calculate the cost of everything that had to do with that sale, for example... the shirt cost me $50. the shipping of the shirt to you cost me $10. the sewing material that i needed to buy in order to fix the shirt (before i could have sold it to you) cost me $5. so my true cost is 50+10+5 which means my net profit is only 35.

now i want all this recorded against your $100 invoice