It is cheaper to buy Chinese domestic and international flights (to near by countries) tickets in China?

I presume you are US citizen or Canadian. Unfortunately the answer is "not cheaper" , again, it depends at what season you would like to buy the tickets. Not forgetting, you are a foreigner, as foreigner, if you buy any ticket from China to any destination will be more than the locals. Simple reason, they would like to make your money. I can suggest you that, if you want to buy cheaper tickets, first you should apply multiple visa, then go to Hong Kong and buy it, is cheaper there.(HK is special adminstration region, is open market there.(since you have already a student visa, travel to HK,or Macao, I am sure you get deal from those places based on what season you are travelling. Check with any travel agency in Hong Kong when you get a chance.

Definitely wait until you get there. China has some AMAZING deals when it comes to plane tickets, as long as they're around the area (East Asia, Southeast Asia). Don't look for tickets in American websites once you get there, you'll get ripped off. Try Chinese websites instead. Some of them are only in chinese, but if you have a friend who speaks and reads the language then buy it online instead. You could try going to a travel agency to buy the ticket in CHina but once they notice you're a foreigner they'll charge you more.

ctrip.com, qunar.com, efares.com

definitely cheaper, especially if you want to buy from this site: taobao.com

recently just found this crazy auction site, Taobao.com, which is China's answer to Ebay.com and has an incredible amount of stuff on offer, basically the sell every imaginable stuff at unimaginable prices..without further crap, check this out:

you can search taobao.com without knowing chinese..

http://taobaobee.com/help.php?action=view&id=83

alternatively you can ask these shopping agent guys for help, if you want to shop taobao.

http://taobaobee.com/

USA to Taiwan to Manila to Taiwan to USA. We went to Taiwan in August, to Manila in December, back to Taiwan in January, and back to USA in June.

It was cheaper to by it all on one ticket in the USA rather than buying the Taiwan to Manila leg in Taiwan.

I think you'd be better to buy your ticket in your home country. The extra leg will be cheaper when it's part of your overall ticket.