It probably depends on how much you need to store. But if you need ongoing backup that will get larger and larger then the answer is probably "No".
I back up my family photos and other important files to Amazon S3 using Restic. My 150GB of data ends up costing me about $1.50/month. I could get the price down lower if I use, say, the Infrequent Access storage tier, but at that price point I just can't be bothered to deal with it.
A free tier often isn't worth it if you have to put any time into thinking about whether you'll exceed the limit. I'd just go with a cheap pay-as-you-go service and not worry about it.
