Seems like 3Docean, an other marketplace besides Turbosquid, is giving a 50% discount during March.
They also have a quite extensive hdri collection, so it should be worth a look.
3Docean Homepage (http://3docean.net/?ref=brainspoon)
I also have my stuff over there: my collection (http://3docean.net/user/brainspoon/portfolio?ref=brainspoon)