If you have access to Excel 2013 (you can get the 60 day evaluation version here), both PowerPivot and Power View are included as add-ins that don't require additional downloads (or SharePoint), just activate them from the File menu, select Options.
Then select Add-Ins from the Options left navigation panel. In the Add-Ins panel change the Manage dropdown at the bottom of the panel to COM Add-ins and click Go....
From the COM Add-Ins popup, check the boxes for Microsoft Office PowerPivot for Excel 2013 and Power View and then click OK to close the popup.
That should add the POWERPIVOT menu to your Excel 2013 menu bar and allow you to build PowerPivot workbooks.
To create Power View reports, just go to the Insert menu and click on the Power View button that should appear between PivotChart and Sparklines items in the ribbon.
With Excel 2013 you can create the PowerPivot/Power View workbook and save them as normal Excel workbooks without requiring SharePoint or other software on your computer.
Microsoft Virtual Labs
Microsoft has posted virtual labs that you access with an internet connection. All of these labs are provided free of charge, but there is a limit of time you can access each lab. This link will take you to a list of all available labs, or use this link to go right to the Power View lab or this link for the PowerPivot lab. There are also some TechNet virtual labs that you can access from this link as well.
The last and most complex to setup option is to build your own complete VM (or VMs). For this option you will have full control over the environment, but you will need to install and configure all of the software yourself. For a complete environment you will need to install Windows Server, SQL Server, SharePoint and Office. For help getting all of this installed and configured in the correct order, see this post put together by Microsoft. This guide is also available, but it is a bit dated since it is using SQL 2008R2 and SharePoint 2010. There is also a guide for specifically setting up SharePoint 2013 or SharePoint 2010. All of the software that is required for setting up this VM(s) is available in evaluation versions, just keep in mind that these versions will expire after a period of time (180 days max). The other thing to keep in mind is that you can buy a TechNet Professional annual subscription for $349 (renewal $249 after first year), you might also find this cheaper online. I recommend the TechNet Professional license over the other versions of TechNet because it does include license keys for all of the Enterprise server products that Microsoft offers.
Microsoft has also provided a version of a VM (previously referred to as the Microsoft All-Up BI Image) that you can download, this VM can be run in HyperV, VirtualBox or VMWare and is available at this location. Here is a review of this VM from Dan English. Microsoft has said that they are working on a new version of this image, but it is currently not available for download.
Personally I like the control of having everything in a VM that I have built, but it is a lot more work. The good thing is you will become very knowledgeable on how to install and configure all of this software (comes in very handy for Microsoft Certifications). I do buy a TechNet Professional license for my own use every year, so this is how I am able to license all of the Enterprise versions of the OS, SQL Server and even SharePoint. I also have Excel 2013 installed on the laptop itself as well, so that I can do a quick demo if necessary without spinning up a whole VM.