Can a person obtain a temporary reduced-cost Canadian passport to go shopping in the USA?

Accordin to the Government of Canada,

The Canadian temporary passport is an eight-page, machine-readable passport. It is:

• issued by a Canadian mission
• used for short-term situations
• meant for urgent, proven travel situations or residency requirements
• based on the decision of the Government of Canada passport/consular officer

This is evidently not appropriate for your application.

However, if you are a resident of Ontario (as I assume because you want to drive to Buffalo, NY), you can obtain an Ontario enhanced driver license at a cost of $40, which is a valid travel document to visit the United States across a land or sea border. (It is not valid for air travel.)

You've misunderstood what a temporary passport is. It's not a short term "passport-lite" that you can get more cheaply and easily than a regular passport. Rather, it's an emergency replacement that you can get from a Canadian embassy abroad when your main passport has been lost, stolen or damaged, to complete your trip and get you back home.

If you are a Canadian citizen and you will be driving from Canada to the USA, then according to the US CBP, you do not need a passport to enter the USA.

Instead of a passport, CBP will also accept:

Enhanced Driver's License/Enhanced Identification Card, NEXUS, FAST/EXPRES and SENTRI enrollment cards.

Note though that if you are arriving by air, you will need a passport (or a NEXUS card when departing from a designated Canadian airport).

Keep in mind as well that while the price is $160, that is a 10-year passport that you can travel to nearly every country in the world on. You used to be able to travel to the US from Canada using your drivers license, however this is no longer the case. The enhanced drivers license is only available in select provinces and it only allows entry via land or sea, and you cannot use this while travelling by air. A Canadian passport is a invaluable piece of ID and you can use it in Canada for any situation in which you need more than one piece of government issued photo ID. This is a situation that happens more often than you would think and the time it saves having a second piece of id when you really need it is almost worth the cost alone. Just my opinion.

Consider NEXUS. $50 for 5 years and only lets you go between Canada and the US. You must visit an enrollment center in person for an interview.