This license and our offers at our website are adressed to independent artists, game-developers and persons who create a product for free or for sale with a final end-user price of less than 25 $ / 25 Euro.

Don't want to make you look bad or nitpick, but it's 'addressed' with double 'd'.

As for the license itself, nowadays such things are becoming more and more common. Sounds and songs that are being sold over the internet ALWAYS have such a license. The whole idea behind it is the fact that this way they can charge you (the indie developer) with much less than they would otherwise. It's either such restrictions or you will pay full price like the big boys. You don't want that, because that'll mean that great model-packs will be too expensive.

Cheers