sub for a day
Add the option to sub for a shorter period than a month, such as a few hours or a day. That way you can watch a streamer's content without being disturbed by ads, but you may not watch the streamer often so no desire or need to sub for a month or more.
Also some streamers stream very infrequently or on a random schedule so being able to sub for a single stream would be useful.
Obviously have it priced lower than a monthly subscription, such as 50 cents per 24 hour period.
also allows you to support a streamer relative to how much they stream