Samsung are about to launch the Galaxy A3 (4.5") £249 and A5 (5") £349 with full metal body and sealed battery not unlike the Galaxy Alpha. These phone were released in other territories at the end of 2014 and will be on sale in the UK on 12th February.
http://www.samsung.com/uk/a-series/?...-hero_20150128
http://www.techradar.com/news/phone-...bruary-1282438
http://www.samsung.com/uk/a-series/?...-hero_20150128
http://www.techradar.com/news/phone-...bruary-1282438
) and from memory was not that expensive.