Sophie spent $18.50 × 2 = $<<18.5*2=37>>37 on the two shirts.
She spent in total $37 + $63 = $<<37+63=100>>100 on clothes so far.
She has $260 - $100 = $<<260-100=160>>160 left to spend on clothes.
Sophie has $160 ÷ 4 = $<<160/4=40>>40 left to spend on each additional item of clothing
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