SQL Server + Microsoft Business Intelligence -- free version or online learning environment?
Evaluation Edition is Enterprise Edition with a timebomb (180 days). It includes SSIS, SSAS, SSRS, etc. So you can evaluate that for 180 days to learn the ins and outs of BI.

Developer Edition, also, provides these tools for ~$50-60 (Microsoft sells it direct for $59.95, though you may find it cheaper from other retailers). The difference is no timebomb but a vastly different EULA. (And if you have an MSDN subscription, you can get this edition - well, any edition - for free as part of your subscription. But there are still licensing restrictions on use, so please pay attention to the EULAs.)

There may also be ways to evaluate these features in the cloud, using Azure Virtual Machine images. I haven't done this, so I don't know if there's any way to take full advantage of this without incurring some level of cost, but I'm pretty sure you can sign up for a trial (I'm also pretty sure it will be significantly less than 180 days).

Also SQL Server Data Tools (SSDT) includes some additional features around building and maintaining solutions that might be useful.