It sucks that the Apple Pencil doesn't work with iPhone. When you get a bigger screen and try with the iPad, it feels so good. I think the cheapest option for the iPad/Apple Pencil would be Apple's entry-level 10.2-inch iPad with the 1st-gen Apple Pencil. That should work well enough. If you have the extra money, an iPad Pro and 2nd-gen Apple Pencil are an even better option, but that gets to be about twice as much.