If you are looking for a cross-body bag for your iPad/laptop I have been using one that has worked perfectly for me.
It is called the Solo New York Ludlow Universal Tablet Sling bag. You can see a photo of it to the left. It easily fits most ipads and my 13-inch Macbook. The strap is wide and strong and I have used it to take my laptop to work when I travel.
Since it only costs $35 it seems to me to be a good value. As you can see there are pockets in the front to carry other things and you could easily put in your wallet, keys, or any other things you might carry with you.
Has there been a downside? Not really. I can fit it under my coat so when I am walking people don’t even see that I have a package. It makes me look a little fat but that is ok. I don’t mind looking fat if it means less likely that my bag will be stolen.
I looked for a long time for bags that would fit a standard iPad and be strong enough to carry a laptop. I have fit both in here without any issues. I was so pleased when it fit my older iPad.
I gave one to a friend to use for her Surface laptop. I think that most 13-inch devices would fit and even have room for a power charger if it is shallow and small. Still, it is easier to just buy a second power charger and not unplug it and move it if you are shuffling between locations. That has worked well for me and prevents the apple cord from wearing down like it always does when you use it.