So first you would have to divide overall price by the number of jeans to work out how much one pair would be
Old Navy : $24 ÷ 3 = $8 for 1 pair.
Wet Seal : $16 ÷ 2 = $8 for 1 pair.
Marshalls : $39 ÷ 4 = $9.75 for 1 pair.
The store with the best deal would be either Old Navy or Wet Seal.