That's absolutely bananas! That very well may be the best deal ever.
As a matter of fact JUST this afternoon I had measured the top of my van so I could try and squeeze as many panels up there as possible and my dodge caravan is 100" x ~52"
If these suckers are 48x26 I could fit 4 of them crosswise on my roof with 4 inches of overhang.
If they are in fact 300w that's 1.2kw of solar for under 500 bucks. Crazy! Originally I had hoped to fit 3 250 watt panels from Santan solar or someone more local to me but their size would make them look utterly ridiculous.
I'll surely keep an eye on them when I get paid again.