To further reiterate.
I don't waste my time with claiming any phone expenses. But if I advertise the rental on the internet and pay for that advertising, then I claim that expense in the "Advertising" category for the rental(s) that specific advertisement applies to. But I don't waste my time with claiming the monthly cost of Internet in my house where I live, since I'd be hard pressed to prove to the IRS that I use it for even 1% business use against my rentals.
Overall I really don't pay for any advertising. I find that a "for rent" sign in the front yard will usually start the phone calls before I can even get home to list it on an advertising website. But when you're in a situation like my son is, that's different. He owns a condo unit he rents out, and yard signs of any type are not allowed.
