Can someone explain to me what the average foreign worker gets? Especially those working in the construction industry?

What's the typical monthly salary? ($500 to $1500 is my understanding)
Are they subject to any special taxes/levies?
Do they receive any other benefits such as accommodation or healthcare, and the out-of-pocket cost of these?

I have one link with some information but it has limited details:
://news.asiaone.com/print/News/Latest%2BNews/Singapore/Story/A1Story20121209-388579.html

I'm trying to figure out how much they get, including any extra benefits.