There are many Mandarin frequency lists which show the relative frequency of Chinese characters. For example, the Chinese Text Computing web page has several lists of Chinese characters compiled from various sources.

However, Chinese words are often composed of more than one character, so lists of single characters can be deceiving.

Here is a list of the most common Mandarin words, as opposed to individual characters. Some of the entries are individual characters, but the majority are character compounds which form Mandarin words. Adapted from the Steering Committee of the Test of Proficiency - Huayu

•ma

Traditional: ?
Simplified: ?
Pinyin: ma

Meaning: (question tag)

•mama

Traditional: ??
Simplified: ??
Pinyin: mama

Meaning: mama; mommy

•ma

Traditional: ?
Simplified: ?
Pinyin: ma

Meaning: horse; horse chess piece; Surname

•mashàng

Traditional: ??
Simplified: ??
Pinyin: mashàng

Meaning: at once; right away; immediately

•máfán

Traditional: ??
Simplified: ??
Pinyin: máfán

Meaning: trouble; troublesome

•mai

Traditional: ?
Simplified: ?
Pinyin: mai

Meaning: buy

•mài

Traditional: ?
Simplified: ?
Pinyin: mài

Meaning: to sell

•màn

Traditional: ?
Simplified: ?
Pinyin: màn

Meaning: slow

•mànmàn

Traditional: ??
Simplified: ??
Pinyin: mànmàn

Meaning: boundless (place); long and slow (time)

•máng

Traditional: ?
Simplified: ?
Pinyin: máng

Meaning: busy