Subscription unlocks all the functions you can't use in demo mode. Once you subscribe you'll have access to all present and future collection types, image upload and daily statistics.
Please remember that Sora is (and will remain) completely ad-free, and it was built by only a few people. We aren't a big company (yet ;) and we aren't vc-backed.
I use digital ocean. The minimum buy in is $60/year, and it gives you 250gb of storage and 1tb of bandwidth, across as many spaces (ie buckets) as you want.
I also use this as my "share" site, and for a bunch of other uses, so my ~2gb of image hosting is just a fraction of that yearly $60.
The major catch is they don't offer dynamic image resizing. I only resize my images to a few standard sizes and just use a small script to resize + upload in one shot.
Please remember that Sora is (and will remain) completely ad-free, and it was built by only a few people. We aren't a big company (yet ;) and we aren't vc-backed.