The words a lot must be written as two words. The phrase has the same meaning as both many and much and can be interchanged with either one.
A lot is followed by of when the meaning is general or by of the when the meaning is specific:
Example Meaning
People A lot of people have done research on discrimination practices among employers. General meaning
A lot of the people at the meeting disagree with the market strategy presented. Specific meaning
Money A lot of money is spent on the battle against AIDS. General meaning
The committee used a lot of the money surveying the population. Specific meaning
Sometimes, a lot can also end a sentence, but it is considered an informal expression:
We laughed a lot.
The budget for the universities in the state of Minnesota has grown a lot.
Examples, that's all.
