I concur with above, and will add that Beijing can be adapted to fit any budget. If you want western-style meals with wine, it will cost you, but for Chinese and relatively standard bar/club entertainment, maybe even Chinese shows and things, it can be quite cheap. Local transportation--mass transit and public--is cheap by just about any standards. Beijing is more expensive than Bangkok, however. Or to look at it another way, for the same amount of cash, you will get less value for it.

Tailoring: Beijing is not known for this, never has been and likely never will be. If you want competent tailoring with a quality level that will last a while, you'll need to go to a place like Dave's at Kerry Center, and pay the price. If you just want a copy made however, of something that fits you well, go ahead and give it a whirl at one of the mass market/factory tailors like Lisa's at 3.3 Sanlitun, Alice at Yaxiu, or 2nd floor of the Friendship Store, Sanlitun Branch.