I did get it when i got a new car in 2002 it was from ming paint protection and i loved it because it did help with dirt and made washing of the car a breeze. However it cost me $400 and that was on a 40 grand car.
But for you i wouldn't bother really you can get a lot of polishes for that much and the protection really needs to be done every 2 years anyway.

I never buy it! You can do it yourself (or have it done by a detailer) much more cheaply.
This thread sums it up: Whirlpool - Alert

Do NOT buy any car extras through a dealership. Dealerships make more money on extras sometimes than the car itself! Rust protection, pain protection etc its all a joke. If you really want it done, do it yourself or get another third-party to do it! Even tint, (just on the front windows in some cars) costs at a dealership $400. You can get it done by a third-party for $200.
This comes from my dad being in the business for over 16 years.

no way! paint protection isnt really worth it unless you have an expensive car(dont know how much youre paying for the corolla) but even then $900 is a large amount to pay

Ah thanks guys - looks like I won't be going with it then.

check out detailparadise.com.au, should be able to get the info you need to protect the car better than the dealer paint protection for under $100+some time (if you can control yourself - detailing etc can become addictive and expensive!)