User Activity

As eBay fees, it's FREE for first 30 listings per month. So is it counted by first day of the month or by the day you list your first item in the month?
I've seen a lot of sellers having multi items on their site. And inside the description section, at the end there're the words say "see my other items" - then u can click on that quote to see more varieties things they're selling. Im a new seller so ...