Lot's of places sell that kit and that price seems to be on-par with all the other vendors.
I have a set of those in 3/8" shank and there are times they really come in-hand because of the unique angles some of them have. In my view of things, they are "essential" for me but probably not so for a home user. A gunsmith might need them more regularly because you find yourself in tight situations more often.
As someone mentioned, the insert costs are a consideration. Those little guys take common -but slightly less popular inserts. They're easily available on eBay but, overall cost is a little bit higher -but it won't break the bank. The threading and grooving insert tips... I've never been able to find replacements for those -but no big deal as I use different solutions to address those things.
If you're on a budget, you'll do really well with the common, 5 piece basic set that just uses Txxx type inserts that can be found just about anywhere.
Ray