I don’t think I’m going out on a limb by saying uploading photos and videos is what most people use the storage space primarily for. I mean, you got to fill it up with something.
edit to add unless maybe you’re talking about the free 5GB of space everyone gets?
I would drop the found phone into the mailbox and maybe the post office will sort it out. 
It’s the only thing I use iCloud for. (Oh, wait, I mean, there’s automatic backups there, I guess, but, otherwise, nothing but that and photos.)
Yes, the basic space that comes with the phone. No one I know rents extra, but it looks like others have different experiences.
As far as I know, there’s nothing in my cloud. I never look at it, so technically, I can’t say that’s absolutely true.
I pay the buck a month for 50GB.
Here’s what I did. I turned it on after charging it. A notification popped up saying that there was a text from Sally Smith (or whoever). I googled Sally and found one who was a concierge at local hotel casino. I called the casino and got her. I told her what had happened and she immediately said a friend had lost her phone and was freaking out about it. The friend then called me and picked up the phone the next day. Apparently, she left it on the roof of her car and drove several miles on a busy road before it fell off. Without the notification and full name, there would have been nothing I could have done.
On my lock screen I have a message that says “Found me? Call 123-456-7890” (wife’s #). I left it in a diner once and they called the number within minutes. I had already realized my mistake and turned around but I would have retrieved it eventually, in any case.
Me too.
Yeah, my lock screen says “if found, place contact emailaddress”. I figure if an honest person finds it i want to make it easy to reach me.
So what happened to the phone from the OP?
Dumped at the Apple store, an hour drive away, at the first convienient opportunity… No idea after that.
Now I see ads they are giving v13 away. Sigh.
I assume the Apple store has some way of tracking down the actual owner? For one thing, I assume there’s a way the store or Apple corporate can look up the owner based on the serial number on the back of the phone?
And I think they’re giving away the iPhone 13 only if you agree to sign up for service from ATT, Verizon or one of the other carriers.
Everything I’ve looked up seems to say that, no, they won’t bother trying to find the owner. (Unless maybe it’s signed up through them – I don’t know what the deal is when you buy an iPhone from an Apple Store itself.) From what I’ve read, if you know what carrier the phone belongs to, you’ll have better luck taking it to them to return it to the owner, but apparently Apple can’t be arsed or doesn’t have a system in place to do so. Once again – from all that I’ve read. I haven’t been able to find anything to the contrary.
I wonder what the Apple store told the OP when he dropped it off. Did they admit that they don’t have a process in place for such things? And how could one tell which carrier the phone is tied to? It seems that Apple stores are better able to help.
On my phone (iPhone 12), you can see the carrier’s name in the top left when you wake the phone (or at least you can see what network its connected to, which in my case, T-Mobile, is the same as my carrier.) If you can get into the phone, then somewhere in your settings or whatnot that information is available, but if you can get into the phone, there’s other ways you have of finding the owner.
Is the process much the same with a found Android phone? Try to identify the carrier and get the phone to them?
I don’t have any direct knowledge in this area, so this is all guessing. I would think that would be the best bet if you don’t want to just drop it off at the police (who I’m guessing are not going to go out of their way to get it back to the owner.)
As for the a little more on returning phones to Apple, I did want to say that on their own Q&A section of the website, people have asked about returning phones and the answers are generally like this one:
Unless the owner put it in lost mode so that it displays contact information on the lock screen, no. Turn it over to the police. Apple will not get involved.
(And that was an “Apple recommended” answer, so it’s gone past an Apple employee’s eyes. Other posts on their own website have said similar.)
Another thread states: “Apple does not get involved with lost or stolen phones.” It’s not from an employee, but this information seems to be repeated on their forums and at least not corrected by Apple, so I’m inclined to believe it’s correct.
I’ve found lost phones on at least three occasions, and each time I had someone call it in panic within half an hour. Where do you guys live, that people are so blasé about losing phones?
Where the OP lives, the ski trails are paved with lost smart phones. 
I once found a phone while walking and it was unlocked. I just went into the contacts and called “Mom” and said I found this phone, and told her where I was dropping it off to go pick up later. She was confused at first, but ultimately thankful. But, how often do people NOT lock their phone (or have it set to lock on it’s own)?
I have it now set to a Face ID and a back-up 4-digit code (because the Face ID is so easy), but for the most part, I’ve never left my phone locked before that. I would go a few months using the passcode, then just getting pissed off at it and leaving it off. Haven’t lost my phones yet, and if I do, I can remote wipe 'em easy enough.