Looking on the internet deeply has found these results:

at the end of the month is the most popular phrase on the web.

on the end of the month 19 results on the web	at the end of the month 1199,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	She always pays at the end of the month. Interest kicks in at the end of the month. I'm getting released at the end of the month. Normally, in a good business time, you could pay your bills and have a bit left at the end of the month. I'm leaving Sacred Heart at the end of the month. My daughter gives birth at the end of the month. I'll submit my reports at the end of the month. Look, when you bring your pay home at the end of the month... she doesn't want an aspirin then.

on the end of the month

19 results on the web

at the end of the month

1199,000,000 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

She always pays at the end of the month.
Interest kicks in at the end of the month.
I'm getting released at the end of the month.
Normally, in a good business time, you could pay your bills and have a bit left at the end of the month.
I'm leaving Sacred Heart at the end of the month.
My daughter gives birth at the end of the month.
I'll submit my reports at the end of the month.
Look, when you bring your pay home at the end of the month... she doesn't want an aspirin then.