Viz-People has just released a set of 10 spherical HDRI files free for non-commercial use.
The images in the HDRI v1 collection are all 6,000 x 2,900 pixels in size, and come with with a PDF catalogue showing not only each image, but the result when it is used to light a standard architectural scene.
The commercial version of the collection, which doubles the image resolution, costs €50 (around $70).
Viz-People also offers sets of cutout characters free for non-commercial use, accessible via the link below.
Download the HDRI files and cutouts (registration required)