I had only been aware of the $1.99 face protector, which actually seems pretty decent, as it covers the entire front of the player.
Although the invisibleShield looks nice as well, I agree with you as to the price (you could buy another Clip for that). Although I also found it a bit cheaper separately at Amazon.com, at $14.99.
Between the 2, the invisibleShield, I’m guessing, is thicker, and perhaps a bit shock-absorbing. But as people say that the Clip+ is very scratch-resistant to begin with, the $1.99 version may be just fine.
For whatever it’s worth, I went to the invisibleShield website (zagg.com) and they offer 3 levels of protection for the Clip+, from $9.99 (screen protector) to $14.99 (2 types of full body coverage, one of which seems to be what’s at Amazon–I can’t tell which, though). The manf. also offers a 45-day money-back guarantee at its website, if you decide you don’t like the product (it’s unclear to me if that refunds the shipping, $2.99 in the U.S.).
Personally, I’d like you to try the invisibleShields (all types) out, so that you can report back to us.
When I got my Clip+, I managed to snag a DLO Action Jacket case (plus velcro armband) for it, which I like: it’s full body protection; it’s stylish; it has an almost full-face sheet of clear acetate on the front, protecting the Clip+ but still showing it off; and it adds some padding for the front and sides/corners/edges of the Clip+, which I really like (I can be a klutz). I got it at a great sale price–no way was I going to pay the original $30 sales price.
Checking at Amazon.com just now, though, I saw that you can get the DLO case from a 3rd-party store there at $1.95 + 5.78 shipping. At that price, I’d be very tempted to grab it, as long as you’re fine with its fully body, fuzzy neoprene cover, which adds a small amount of bulk to the player (but which leaves all controls accessible). A nice advantage it has over the invisibleShield, beyond the price, is the shock-absorbing nature of the case. It’s unclear to me how many cases the third-party store might have.
At any rate, I hope this helps. Go to it, and let us know how it works out!