Sentences with same word and a different meaning

[BlackCitadel]

Like, go a head and pay the money..
Or
Go ahead and pay the money..

Which one is correct?

[Dozy]

You cannot interchange "a head" and "ahead". "fifty pounds a head" does not mean "fifty pounds ahead".

"Go ahead and..." is correct. "Go a head and..." is wrong.

[BlackCitadel]

Thank you so much, i understand the different now.
But will the teacher understand this example???!!!
They paid fifty pounds a head.
I guess he will not!
OK, how about if I said it like this:
They paid a head fifty pounds.

[Dozy]

"They paid a head fifty pounds" is not correct.

[Luschen]

The teacher will understand "They paid fifty pounds a head." It is a common expression.

[BlackCitadel]

Thanks.