Solo trip, not including hotels except for the couple I didn't book in Japan because I was looking forward to finding my accommodations on the spot. Out of the couple hotels I stayed in, I think some of the best sleep came from the Capsule Inn's! 30 to 40 bucks a night depending where you stay was totally worth it.
So to answer your question, I pretty much went through Singapore/Cambodia/Vietnam/HK/Beijing only spending 1000$ without paying for the Sinapore, HK and Beijing accomidation.
The other 1000$ I spent in Japan for 12 days. This excludes my JRpass and 3 nights stay out of the 12 days. The rest of my money went towards Capsule inn's, one night stays, gifts, admission and food. Food's expensive in Japan and you get a lot less then in North America. Bring food like granola bars, buy eggs or book hotels with free breakfast

Convince stores serve fresh food daily and it's the cheapest alternative quick on the go food. It's not like North America, the food is actually fresh and good!
I splurged here and there like a sashimi lunch at the fish market for 16$
I'll try to blog more, I'm only on HK so far. If you'd like to ask me some more detailed questions about my trip (food, money, admission) please don't hesitate in msging me!