๐We use a lot of and lots of in informal styles.
๐Lots of is more informal than a lot of.
๐A lot of and lots of can both be used with plural countable nouns and with singular uncountable nouns for affirmatives, negatives, and questions:
โ Weโve got lots of things to do.
โ Thatโs a lot of money.
โ There werenโt a lot of choices.
โ Can you hurry up? I donโt have a lot of time.
โ Are there a lot of good players at your tennis club?
โ Have you eaten lots of chocolate?