>>sell the remaining 3 chips for $1.50 each + .75 each for shipping = $ 2.25 per chip or $6.75 total the fish chip only cost you $ 0.25

Assuming that 75¢ represents your actual shipping costs the fish chip would have cost you $2.50 because even though you collect $6.75 for the three chips you sold, you had to pay out an additional $2.25 so in fact you only net your $4.50.

Obviously your actual shipping cost is probably less than 75¢ but if you sell the chips to three different people then your shipping profit is very little, you make more if you collect $2.25 in shipping to send 3 chips in one package.