How much can you spend if you travel to the US from Canada?

Depends on where you are traveling from and traveling to. More from Florida to Quebec than from Oregon to Saskatchewan. Think man think.

that depends on what your purchase is. general shopping is $200.00 us duty free, but remember to stop at the duty free shop to get half of your taxes back (i think it's the gst). if you make a large purchase you can mail away for your (pst?) tax returned. some large purchases are duty free.

"After each absence of 24 hours or more
You can claim up to CAN$50 worth of goods without paying any duties. This is your personal exemption. You must have the goods with you when you arrive, and you cannot include tobacco products or alcoholic beverages in this exemption.

If the goods you bring in are worth more than CAN$50 in total, you cannot claim this exemption. Instead you have to pay full duties on all goods you bring in.

After each absence of 48 hours or more
You can claim up to CAN$200 worth of goods without paying any duties. You must have the goods with you when you arrive. Although you can include some tobacco products and alcoholic beverages, only a partial exemption will apply to cigarettes, tobacco sticks, or manufactured tobacco. You may have to pay a special duty on these products. You can find more details under the section “Tobacco and alcohol.”

After each absence of seven days or more
You can claim up to CAN$750 worth of goods without paying any duties. With the exception of tobacco products and alcoholic beverages, you do not need to have the goods with you when you arrive. Although you can include some tobacco products and alcoholic beverages, only a partial exemption will apply to cigarettes, tobacco sticks, and manufactured tobacco. You may have to pay a special duty on these products.

To calculate the number of days you have been absent, do not include the date you leave Canada, but include the date you return. Dates matter, not times. For example, we consider you to have been absent seven days if you left Friday the 7th and returned Friday the 14th."