Những lỗi sai:

As more things are make to be sold and more people have services to sell, advertising grows. Today it is one of the biggest businesses. Every year people spend billion of dollars on advertising.

Advertising help sell more things to more people. This in turn makes it possible produce more things to sell. Sometimes it even helps make things cost less. In the beginning, for example, radios costed much more than they do today. Because they were turned out slowly and expensive by hand. Yet, advertising made more people want radios. When manufacturer began making them by the thousands, they found quickly and cheaper ways of do the job. Because advertising encourages us to buy and produce more things, it is sometimes called the spark plug of the business world.

Sửa lỗi, đoạn văn hoàn chỉnh:

As more things are made to be sold and more people have services to sell, advertising grows. Today it is one of the biggest businesses. Every year people spend billions of dollars on advertising.

Advertising help sells more things to more people. This in turn makes it possible to produce more things to sell. Sometimes it even helps make things cost less. In the beginning, for example, radios cost much more than they do today. Because they were turned out slowly and expensively by hand. Yet, advertising made more people want radios. When manufacturers began making them by the thousands, they found quicker and cheaper ways of doing the job. Because advertising encourages us to buy and producing more things, it is sometimes called the spark plug of the business world.

make → made  : Line 1
bigger → biggest : Line  2
billion → billions : Line 2
help → helps  : Line 3
possible produce → possible to produce  : Line 3
costed → cost  : Line 5
so → because : Line 5
expensive → expensively : Line  5 
manufacturer → manufacturers  : Line 6 
quickly → quick  : Line 7