alot, a lot, allot

The word lot is a one-word noun. When you precede it with the article a, you write the expression as two words: a lot. You wouldn’t refer to a tree as atree. Neither should you write alot.

Allot is a verb that means “to parcel out or distribute.”

Example: You would need a lot of money (about $6.2 billion) to be able to allot even one dollar to each person living on the earth today. You’ll need a lot more by the year 2050, when the world’s population is projected to total 9.2 billion.