You better off finding a pair 2nd hand, I think brand new from Nissan is about $200-300.
And without the metal clips, you can still stick it on pretty securely with some strong 3M double sided tape.
As for the snapping, you could try wrapping them in vinyl lol. I've wrapped a few sets of weatherhshields with the 3M carbon fibre vinyl and a couple of sets have been snapped, once wrapped, they are as strong as new
If I get time tomorrow, I'll take a pic of my weathershields that's been wrapped.