If someone enters your shop, and you see whether they are a man or a woman, then you can refer to that particular person, and not to a general person. In the general case you can say

Man braucht Geld zum Einkaufen. 

With a single "n" it means the same as "somebody" or "someone". If you don't like it, you can say "everyone".

Jeder braucht Geld zum Einkaufen. 

Now this is for the case when you are talking about any arbitrary person. If there is a particular person and you don't know if they are a man or woman, you might say

Jemand ist gerade aus dem Laden gelaufen ohne zu bezahlen. 

If someone enters your shop, and you see whether they are a man or a woman, then you can refer to that particular person, and not to a general person. In the general case you can say

Man braucht Geld zum Einkaufen.

With a single "n" it means the same as "somebody" or "someone". If you don't like it, you can say "everyone".

Jeder braucht Geld zum Einkaufen.

Now this is for the case when you are talking about any arbitrary person. If there is a particular person and you don't know if they are a man or woman, you might say

Jemand ist gerade aus dem Laden gelaufen ohne zu bezahlen.