In China the currency used is the local currency, RMB or yuan. People in China do not care for US dollars.

I suggest you type in "tipping" in the search box at the top of this page. The subject has been extensively covered.

In fact, you do not have to tip in China.

Make us happy - please don't tip :)

As suggested do a search on the subject.

Just do per you like.

Tipping is not encouraged in Shanghai.Basically most of the services in Shanghai do not encourage tipping n also do not expect 1 too.Its maybe an exception to the tour companies that some r adamant about tipping to the driver n guide at the end of the tour.Its beter to set the record straight before the start of the tour.If the company has not set a policy on tipping its best not to tip.There r some companies that set a certain amount of tip to the guide n driver n if u r not happy about it u can always turn them down.There r so many tour companies in Shanghai alone.Anyhow if u so decide to give a tip itsdefinately doesnt matter much if u tip in USD or Yuan.Its not insulting but i would feel that they will be more glad if u do so in Yuan.At least it saves them the problem of getting the USD converted to Yuan.Furthermore USD is not as highly in demand now in China compared to several years ago.