Let's take a look at some confusing words:
a lot of /lots of and a lot
Here you can find out the difference in meaning between them and how they should be used.
a lot of / lots of
a lot of and lots of have the same meaning: they both mean a large amount or number of people or things.
They are both used before countable nouns and uncountable nouns:
with countable nouns:
A lot of people went to the game.
Lots of people went to the game.
with uncountable nouns:
A lot of snow falls in winter.
Lots of snow falls in winter.
a lot means very often or very much. It is used as an adverb. It often comes at the end of a sentence and never before a noun.
I like basketball a lot.
She's a lot happier now than she was.
I don't go there a lot anymore