I have helped a few friends purchase vehicles.
One thing with negotiations, do not let the fear of unable to purchase the car scare you.
Remember that there is ALWAYS another dealer who can and will give you a better price.
Never be afraid to get up and walk off after an hours worth of negotiation.
(The amount of times ive done that and got a further ~$2000 off. ).
These are the steps i follow
1. Go around to the local dealer and ask for the price, negotiate for 5 mins (If an ASIAN salesperson comes up to you, tell you're still looking, NEVER negotiate with an ASIAN person, you get no where - Im asian myself).
2. Go the next dealer and tell them price you got (less $500~$100) and see how they react.
In most cases they'll agree. This figure (less another $500~$1000) will now become your basis of negotiation over the phone.
3. Go home and print out the listing of every Toyota (since we're talking corollas here) dealer there is in your city. Call each and every one of them one by one, and ask what their price is.
You may get an answer of "come in and we'll get you the best price"
Here's what i normally say
"I'll just cut straight to the chase, ive already been offered a Corolla from another dealer for $xx,xxx with mats, tints, spoiler, etc" (dont go overboard and say things like 17" rims and side skirts etc cos they'll know you're lying unless the price is realistic).
"Can you do better?"
Ok, how much?
If they say just come in and we'll get the best price, just cross them off your list.
They might ask if the store has the car in stock, always answer YES and tell them you saw the car in the colour you wanted sitting in the yard. (This is because some will say "they dont have it stock thats why, but we do, hence we charge more").
The trick is find someone who looks like they really need to sell or they'll get an ***** whooping from their boss.
If you call the same dealer 30mins later, more than likely you'll get another guy who is more desperate than the first.
4. Visit the dealers you have built rapport with and given you a good price.
5. Talk to them about the price mentioned on the phone and push it down even further.
One of the cheapest (but not always) Toyota dealers in Sydney ive noticed is Phil Gilbert @ Lidcombe.
I was told by an ex-employee @ Toyota Clintons Lakemba that Phil Gilbert go by volume and use the bonuses they get from Toyota to compensate, how true this statement is I have no idea.