Locally the dealer wants close to $10 each IIRC. $5 shipped isn't bad though. Not huge on buying bulk for my moms car at least because she might not have it much longer.
I have used them at every OCI in my Kia. In the wife's Santa Fe I normally use them also, with 2 exceptions. On the third oil change in her car I used a pure one and then the next I used a Napa silver. No issues at all.