A new, cheaper PlayStation 3 will be released in Japan next Thursday, August 28, Sony has announced. The new 500GB Charcoal Black CECH-4300C model will be available for 25,980 yen + tax (£151), almost 3,000 yen (£17) cheaper than the existing model. The current 250GB/500GB black and 250GB white PS3 models will also be discontinued,…