A school is going to give each of 300 students a paper cup. The price of each cup is 2 yuan. There are three stores A, B, and C that sell this kind of cups. Store A offers a 15% discount, store B buys 9 and gets 1 free, and store C offers a 20% discount. Which store do you think is cheaper to buy? How much did you actually pay?
某校准备给300个学生每人发一个纸杯．每个杯子标价是2元，有甲、乙、丙三家店都卖这种杯子，甲店优惠15%，乙店买9送1，丙店打8折．你认为到哪家店购买便宜？实付多少钱？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 * 300 * (4/5)</gadget>
<output>480</output>

<result>480</result>