If you're a mechanical engineer working a decently big company, you'll have unlimited to them (good fun). Otherwise, do you live near a university library or know someone with a university id? I used to be able to unlimited online access through my university library website, too.
Try checkout craigslist or something once in a while? I used to work in a place that actually bought the full bound-paper collection every 3-4 years. Not sure what they did with the old copies though.
And in the even less legal realm, a quick search on sketchy torrent sites seems to turn up results. Good luck.
I'm curious though: what would the average homeowner need to look up in ASTM standards?