The pricing change was in response to a growing user base, and demand for volumes greater than 2GB/day.
Loggly still offers a free plan which supports 200MB/day and retention of 7 days. There is also a beginning paid plan that starts with 200MB/day, but has retention of 15 days, starting at $8/month.
Loggly is also adding support for secure syslog (TLS), HTTPs on web inputs, and log archives on all account levels including the free plan.
This is a great example of Software as a Service (SaaS) and API service providers innovating around monetization and trying to find the best approach that fits their customers needs and the services they offer.