Is it grammatically correct to use the word "between" when referring to the twins and me having only two dollars?

Yes, it is grammatically correct to use the word "between" when referring to the twins and yourself having only two dollars. The word "between" is commonly used to indicate a relationship or comparison between two or more things. In this case, you are comparing the amount of money shared among three people (the twins and yourself) which is two dollars. The sentence could be constructed as follows:

"The twins and I have only two dollars between us."

To determine if it is grammatically correct to use "between" in this context, you can follow these steps:

1. Identify the subjects: In this case, the subjects are "the twins" and "I" (referring to yourself).
2. Determine the relationship: You want to express that the amount of money is shared among the subjects.
3. Use the word "between": Since you have two subjects, "between" is appropriate to indicate the relationship of sharing or comparison between them.

Always remember to consider the grammatical rules, context, and purpose of your sentence when constructing it.