There are 12 bags of kudzu powder in one box, a special product in Sui County, and the price of each bag is 15 yuan. During the May 1st promotion, store A will reduce the price by 15% for each box, store B will buy three bags and get one free; store C will sell each bag at 30% off ． Congcong wants to buy a box of kudzu powder, which store is the cheapest? How much is the minimum cost?
随县特产葛粉一箱共12袋，每袋售价为15元，五一期间镐促销活动，甲商店每箱降价15%，乙商店买三袋送一袋；丙商店每袋按七折出售．聪聪想买一箱葛粉，到哪个商店买最便宜？最少需要多少钱？
<gadget id="calculator">12 * 15</gadget>
<output>180</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">180 * (7/10)</gadget>
<output>126</output>

<result>126</result>