The average life-span of Hewlett-Packard USB100 laser printer is 4 years, and its market retail price is 1200 yuan, and cost is 45% of retail price; The market retail price is 180 yuan, and the cost is only 50 yuan. A merchant has adopted the promotion method of "buy 10 ink rollers and get a USB100 printer for free" in its operation. According to the merchant, every time they send out a printer, they will deduct 4% of the actual turnover. pay sales tax), how much is the actual profit?
惠普USB100激光打印机的平均寿命是4年，它的市场零售单价为1200元，而成本是零售价的45%；在4年中平均每年要用2只与之配套的墨滚，而墨滚的市场零售单价为180元，成本只有50元．某商家在经营中，采用了"购置10只墨滚，送一台USB100的打印机"的促销方式，如按商家说法，他们每送出一台打印机，扣除实际营业额的4%的营业税(赠品免交营业税)，实际获利多少钱？
<gadget id="calculator">180 - 50</gadget>
<output>130</output>

<gadget id="calculator">130 * 10</gadget>
<output>1_300</output>

<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1_200 * (9/20)</gadget>
<output>540</output>

<gadget id="calculator">4 / 100</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">180 * 10 * (1/25)</gadget>
<output>72</output>

<gadget id="calculator">1_300 - 540 - 72</gadget>
<output>688</output>

<result>688</result>