The Ambassador Bridge connects Detroit to Windsor, one of North America's busiest border crossings. (Associated Press/Paul Sancya)

Considering a cross-border shopping trip but unsure of what you'll save once you figure in duty, taxes, and credit card fees? Here are some answers to common questions from personal exemptions to bringing back artwork to calculating duty charges.

When is the best time to plan my trip?

It's difficult to predict when there will be a backlog of cars waiting to cross the border. If you live close to the border, you can gauge traffic flow by checking the Canada Border Services Agency's website which updates wait times at least once an hour. Other border offices also have webcams showing traffic waits. Make sure you have your identification ready to make crossing into the U.S. as fast as possible. Anecdotally, some people say if you're travelling on the weekend, aim to be at the border in the early morning — about 7 a.m. — to avoid lineups. Traffic at some border checkpoints also tends to be heavy on long weekends.

What's the best way to pay for my purchases in the U.S.?

Many consumers use their credit cards for ease, but buyer beware: a 2.5 per cent fee for out-of-country purchases is applied to credit cards from TD Canada Trust, RBC, Scotiabank, Bank of Montreal and CIBC. If you plan on spending a lot in the U.S. you may want to consider applying for a U.S. credit card or open up a U.S. banking account.

How much can I bring back with me?

The longer your trip, the more you can bring back. If you are going for a week or more, your exemption is $750 Cdn. You can bring back 1.5 litres of wine or 1.14 litres of liquor or 1.14 litres of wine and liquor, or 24 cans or bottles of beer. You may also bring back 200 cigarettes, 50 cigars or cigarillos, 200 grams of manufactured tobacco and 200 tobacco sticks. You can include tobacco and alcoholic beverages for a partial exemption and you can ship some of your items home before you cross the border. Be aware though the day you left for your trip is not counted as part of the week's seven-day calculation.

If you are away for more than 48 hours, you can bring back $400 worth of goods, 1.5 litres of wine or 1.14 litres of liquor or 1.14 litres of wine and liquor, or 24 cans or bottles of beer. You may also bring back 200 cigarettes, 50 cigars or cigarillos, 200 grams of manufactured tobacco and 200 tobacco sticks.

If you are going for more than 24 hours but less than 48 hours, you can bring back $50 Cdn worth of goods without paying duties. You must have the goods with you when you cross the border and you can't include tobacco or alcohol in the exemption.

If you go for less than 24 hours, you do not qualify for any exemption and must pay duties on all of your purchases.

I spent more than my exemption – can I combine my purchases with another person?

You cannot combine your personal exemptions with someone else's. You may make claims on behalf of your children if the goods purchased will be for their use.

What penalties will I face if I don't declare all of my purchases?

If you are caught lying, your purchases may be confiscated and you may have to pay a fine ranging from 25 to 80 per cent to get the goods back. You may also face prosecution and border authorities have the right to seize the car in which you're travelling and issue a fine for its return.

Border agents will seize undeclared tobacco and alcohol permanently.

If you're caught not declaring goods, you will be entered into the Canada Border Services Agency computer system and you may face scrutiny crossing the border on future trips for up to six years. You can appeal seizures within 90 days of the incident.

I want to bring my camera with me on my trip – how can I flag it so customs agents won't suspect it's a new purchase upon my return?

If you have something valuable you want to bring with you on your trip, ask a customs agent for a Y38 form. For goods without serial numbers, CBSA agents will give you a sticker to mark the product.

The CBSA warns that jewelry is often difficult to identify and therefore include on the Y38 form. You may want to consult a jeweller or insurance agent for an appraisal report. Carry a signed and dated photograph of your jewelry or certification documents to prove that you purchased the items in Canada.

What is the NAFTA exemption?

Many goods made in Canada, the U.S. and Mexico are subject only to the GST and applicable sales taxes. That means you can bring them back without paying duty, even if you're only across the border for a few hours.

The list includes books, cellphones, cordless telephone sets, video games, antiques, most types of original art, picks for climbing or mountaineering, one-handed pruners and shears (including poultry shears), juice extractors, hair-removing appliances, hair dryers, electric irons, microwave ovens, bread makers, indoor smokeless barbecues, and CD players.

The complete list is available here.

If I buy a sweater from a U.S. outlet but it was made in China does it qualify for the NAFTA exemption?

No. Clothes must be made in Canada, the U.S. or Mexico to qualify for the NAFTA exemption. If you exceed your personal limit, you will have to pay duty of 18 per cent in addition to provincial and federal sales taxes.

How is duty calculated?

Duty rates vary according to the item and may vary according to materials used. For example, sandals made solely of rubber have a different tariff rate from sandals made of plastic.

What items do I have to declare?

You must declare the following items if you are bringing them back across the border:

• Meat products.
• Dairy products.
• Plants, trees, cut flowers.
• Wood products.
• Fruits and vegetables.
• Pets, animals.
• Feathers and down.
• Seeds and nuts.
• Baby formula.

If you're planning on stocking up on groceries, you must abide by certain limits of 24 eggs, 20 kg of dairy products not worth more than $20 in value, 3 kg of margarine or butter substitutes, 20 kg of meat products, a maximum of one whole turkey or 10 kg of turkey products, maximum of 10 kg of chicken, maximum of 5 kg of edible meats, meat products from cattle, sheep, goat, bison, buffalo and a maximum of 250 g of caviar.

What other goods face special restrictions?

If you're buying a piece of artwork or an antique you should first contact the Department of Canadian Heritage as certain goods deemed cultural objects may require export permits.

Similarly if you plan to buy a firearm or a weapon, you should contact Canada Firearms Centre for authorization. Explosives, ammunition and fireworks must also receive clearance first from Natural Resources Canada.

Before bringing a car into Canada you must contact Transport Canada's Registrar of Imported Vehicles first to ensure it meets import and Canadian standards.

And finally, if you plan on buying a second-hand mattress you must get a certificate showing that it has been cleaned and fumigated.

What can I not bring into Canada?

Under no circumstances can you bring in obscene materials, hate propaganda or child pornography.