Premium titles, but pretty pricey compared to past bundles. On the other hand, No Starch has never offered more than 35% or 40% off their own books.

System Programming in Linux ebook alone is $80.

If you already have that book go for the 15 items bundle at $36 but bear in mind that two of them are just early access preview.

If you want to learn Linux, go for it. You can't go wrong with No Starch Press and donating to charity, two birds with one stone.