> Is IPFS storage or S3 storage more cheap / economical today?

IPFS still needs a server running to pin the content, so I'm not sure how relevant this question is. Assuming you can assemble a sizable group of users who pin your content, IPFS will be the cheaper option since you wouldn't have to pay for more than the one server, which could technically run from home.

The first IPFS pinning service I found in a search offers pinning at $0.35/GiB/month. S3 shows prices of $0.023/GiB/month.

So no, you can't currently say IPFS will decrease costs compared to S3 *unless* you can guarantee a network of users who are guaranteed to serve as reliable peers for the network *and* you factor in the cost of the main server hosting the files on IPFS.