Complex sentence: It was a shocking event, because the price was around only 3000 yen (30US $), which was half the cost of other companies and aggressive marketing campaigns led to their capturing of large shares of the market.
Split into simpler sentences: It was a shocking event, because the price was around only 3000 yen (30US $), which was half the cost of other companies. This, coupled with aggressive marketing campaigns led to their capturing of large shares of the market.