A project called HDRI Heaven by Greg Zaal might be what you’re looking for.
Finding decent, affordable HDRIs is not that easy, right? Take a look at HDRI Heaven — an awesome collection by Greg Zaal, a CG artist and Open Source advocate who has worked on a few short films, Blender add-ons and training material for sites like CG Cookie, CG Masters and BlenderGuru. Some of the HDRIs there are free. Others are available at a reasonable price (free at a lower resolution).
Greg’s HDRIs are:
As cheap as possible, without compromising quality