(Reuters) - Amazon.com Inc is expected to launch its long-awaited tablet computer on Wednesday, sporting a low-enough price to give Apple Inc's iPad some serious competition for the first time. At a news conference Wednesday morning in New York, Amazon will likely unveil a seven-inch tablet that will let users read e-books, download digital music and video games and stream movies and TV shows. Analysts expect the tablet to be priced around $250, roughly half the price of Apple's dominant iPad, which starts at $499. "If Amazon prices the Kindle Fire at $250, it has the potential to become the...