Hi,
I wish that was true, its quiet the reverse, Toyotas own parts are virtually always the most expensive by a very wide margin, thats why there is such a strong aftermarket for parts.
What country are you in ?
Hi,
If you want to use Toyota Oil then fine, always your choice and while the cars is under Toyotas warranty probably a wise thing to do.
However I like many others have run Avensis and Corolla to 100K ++ miles on other oils without problems.
There are many well known brands out there like Castrol, Shell, Coma but to name but a few, and all should serve you well, as they have me, just make sure you get the right grade for your engine, nearly all the oil companies have a car /oil type checker on their web sites.
You may find even the big supermarkets have special offers on some of these big name oil from time to time.
If changing brands, just make sure you do not mix the two oils together.