Watch importer Mr Chang, 43, never rushes when it is time to shop for a car. Or, more correctly, when he shops for a COE.
"I watch the trend, and I go by gut feel. But I'm not always successful," he says.
That is modest, coming from someone who has secured three low-priced COEs in the last nine years - one every three years.
In December 1997, he paid just $50 for a COE, at a time when prices had been hovering between $60,000 and $70,000. It was a fluke result, at a time when the system was 'closed' (when bidders could not see how much was being tendered).
Prices bounced back to around $44,000 the following month (tenders were monthly back then).
Mr Chang, a motorsports fan, had been bidding for a few rounds before he landed the 'lottery' COE, as he had a feeling the prevailing rates were too high to be sustained.
He used his cheap COE to buy a Citroen.
Then, in January 2001, he secured a COE for $15,001 - half the going rate at the time.
"That was more luck than reading the market correctly," he confesses. He bought another Citroen.
In February this year, he got himself a COE for $5,200, which was again half the prevailing premium. He hasn't decided on what to buy with it.
Mr Chang is aware that not all car agents will give a decent deal to customers who walk in with their own COE.
"You must go to distributors who are willing to negotiate," he advises, adding that these tend to be those selling the less sought-after brands. "It's market forces," he says.
He believes bidding for your own COE is not always worth the effort. "If you see that the premiums are quite firm and the packaged prices are attractive, forget about bidding on your own," he notes.
DIY bidding for a COE works best when you think prices are on their way down.
One last word of advice from him: "If you want to fully enjoy a low COE, you have to keep the car as long as possible."
If you sell or scrap the vehicle before its 10th year, the residual value will reflect - punishingly - the low COE.
MR STEVEN TEO, regional manager
Mr Teo, 51, believes more can be done to encourage car buyers to bid for their own COE.
For starters, he feels the Land Transport Authority should collect a smaller deposit from bidders. Currently, you must have at least $10,000 in your bank account to bid.
His experience as a DIY bidder has left him feeling that car dealers should not be allowed to bid on behalf of buyers - or at least, they should dish out better treatment to those who turn up with their own COEs.
"When I got my own COE eight years ago, I had to go around looking for dealers who would give me a reasonable deal," recalls Mr Teo. "I ended up buying a demo car from Honda agent Kah Motor."
Then, three years ago, he landed another COE on his own. He bought a Volvo S60.
"The distributor was quite good. The COE was $20,000 but they offset the selling price by $22,000," he says.
Mr Teo, who is the regional manager for a multi-national company, does not like the way some dealers set their rebate levels - the point at which they give buyers a refund if COE prices fall. So, rather than feel sore if that happened to him, he's chosen the DIY way.
Mr Lee Chiu San, general manager
If you want to do it yourself, accept the reality that most leading car dealers won't give you the same price as the next buyer who lets the dealer bid for the COE.
That is the advice of Mr Lee Chiu San, 60, general manager of Chevrolet dealer Starsauto, and someone who has got his COE the DIY way.
Speaking in his personal capacity, he says buying a car is like buying any big ticket item.
"If the queue for a condo goes round the block, the seller would not entertain any bargaining," he says. "If the building has been empty for months, the seller will throw in whatever you want."
The top dealers sell thousands of vehicles each month. Simply put, buyers who choose the package deal of car-with-COE come first, and few dealers would let someone with his own COE jump the queue for delivery of a car.
Mr Lee says buyers with their own COE can still get good deals if they choose a car that is not among the top 10 most popular here.
He should know. He landed a $6,002 COE last month - less than half the price of prevailing premiums - and has booked a Volvo C30.
Volvo ranks 14th on the sales chart.
Y.P TANG, business development manager
Mr Tang, 37, missed out on a cheap COE six years ago when he bought a Honda Civic.
Dealer Kah Motor had the colour he wanted, and so he chose the Immediate Delivery package, which meant he got his car with an Open Category COE.
"If they didn't have the colour, they would have gone for bidding. And they would have got the $101 COE," he says.
The going rate for a 1.6-litre car COE then was between $28,000 and $36,000.
Two months ago, the business development manager got a second chance. A car dealer friend had told him that premiums were likely to plunge in the tender just before Chinese New Year.
So Mr Tang went to an ATM, put in his bid and waited. A few days later, he was elated to learn that he had secured a $5,200 COE - less than half the average prevailing rate.
Mr Tang, who owns a Subaru Impreza WRX, bought a Toyota Yaris (above) for his wife Sharon. He paid around $44,000 - nearly $10,000 less than the packaged price then.
He had no problem buying a car with his own COE. "When I went to Honda, they were also quite willing to sell me a car," he says.
Anyway, his attitude is that when it comes to the deals offered by different agents, it is always a 'willing-buyer-willing-seller' arrangement.
"If you look around, there are different prices for the same car everywhere. It depends on how much of a loan you take and for how long," he reasons.
The bottom line? Nobody forces you to accept a deal, he says.
