I went with Saudi to Manila via Riyadh in January from Heathrow. Cost me £444 but you can get it cheaper, around £380 is the cheapest I've heard but you might need to be flexible on your dates and may have to travel on a weekday to get these prices. The airlines OK but nothing special but you'll need a visa to leave Riyadh airport. Like Englishman said, go direct to the airline or try netflights.