International flights out of China RMB 90. Domestic flights have mostly been standardized at RMB 50. This is included in the price of the air ticket--if you look at your paper ticket or e-ticket, there will usually be a line item at the bottom where you'll see this. There is NO MORE cash collection of this fee at any airport nor has there been for a number of years.

I also have a question about a trip to China; I heard there was a $100 coupon off a round trip? anyone know anything about this??

What sort of round trip are you talking about?

would be from California or Washington to Beijing i think

It's impossible to comment on the fare deal you're contemplating in the absence of any details, but you should be aware that spreads of $300-400 are common between booking channels (i.e. Gateway v. united.com), so there's a good chance that your $100 coupon is worthless in the grand scheme.

Also, from LAX/SFO/PDX/SEA, it's often possible to get air + hotel for less than the cost of air alone. The hotels these junkets use typically aren't extremely convenient and you'll be given pressure to participate in time sucking group tours/meals, but this option is still worthy of consideration.