So, remember when you were a kid and you'd go to the newsagents and see like a sheet of lots of little stickers? My idea is basically to offer users the option to purchase a "sheet of emotes".
Stay with me here.

I see a lot of emotes that I love on channels that I don't really care for or watch enough to want to subscribe to. I can't justify to myself paying $5 a month to a channel I don't watch just so I can use their emotes in the chat/discord of a channel I do watch.
So my suggestion is this; pay, say $1-$2, to purchase a "sticker sheet" from a channel. The you'll get 100-150 uses of all the emotes of that channel. When you've used up all your uses, you can just buy another sticker sheet.

Obviously there'll be some logistics to work out on Twitch's end. How to track the emote uses; how to avoid people exploiting the system some how so that their uses don't get used up; exploring the possibility of allowing the use of and tracking emote uses in discord.
I think if you can work all of these things out though it would be a feature that many users would take advantage of, I know I would.