Perhaps better explained on the enterprise blog
So, individual accounts are still available, small business gets folded into regular business accounts ($50 per user per year)
Please note this change has no impact on our existing customers, including those using the free version. And as before, Google Apps for Education will be available as a free service for schools and universities. Also, as the first cloud productivity suite with FISMA certification, we’ll continue to offer Google Apps for Government for $50 per user, per year.