Enough progress to justify spending $15 (less than the price of dinner downtown)? I agree, many find the revenue models / cost structures of professional organizations outmoded. However, I find this rather harsh aversion to paying a few bucks for peer-reviewed, scientific content curious.
If it's of any help to you, many public universities, schools, and local libraries provide full access to ACM content, often both on-site and off. The most common method of providing access to this is via EBSCO's "Business Source Premier" database. I frequently read ACM articles from my desk via the web; a quick title search in EBSCO will pull up the title in about 20 seconds, and I can download a PDF of about any article published since 1965 to send to coworkers.
That said, if price is an issue, please check with your local library. Odds are good that your tax dollars are already paying the cost for you to read these articles from the comfort of your home or office. This isn't just true for the ACM -- even in the age of paywalls, your library's probably been quietly working to provide digital access to all of this for the past decade.