Is putting a comma and then because grammatically correct?

No, putting a comma and then "because" is not grammatically correct.

Here's why:

* "Because" introduces a dependent clause. A dependent clause can't stand alone as a complete sentence.

* Commas separate independent clauses. Independent clauses are complete sentences that can stand alone.

Here are some correct ways to use "because":

* Using a comma and a conjunction: "I went to the store, because I needed milk."

* Using a semicolon: "I went to the store; I needed milk."

* Using a colon: "I went to the store: I needed milk."

Incorrect Example: "I went to the store, because I needed milk."

Correct Examples:

* "I went to the store, and I needed milk."

* "I went to the store; I needed milk."

* "I went to the store: I needed milk."