Depends where from, where to and how heavy it is.
it depends on the stamp then you will know how many stamps you will need
how many first class stamps does it take to mail a 4 oz letter and package
this would depend on the weight of the package
80
23-30 stamps depending on the weight of the package.
It depends on where from, the weight of the package and what transport is used.
For a 5-ounce package, you would need to use enough stamps to cover the postage cost. In the US, the current rate for each additional ounce in a package is $0.20. Therefore, you would need to calculate the postage cost based on the total weight of the package (5 ounces) and then affix the appropriate number of stamps to cover that cost.
You need 1 stamp to mail a letter/package throughout Canada
That will depend on the weight of the package and the postal class (e.g. parcel post, media mail, priority) of the package.
You would really have to know the weight and dimensions
The answer depends on the size of the cards. It could be just one large package.
To mail a 12 oz package using Forever stamps, you would typically need to use the postage rate for the package weight class. As of my last knowledge update, a 12 oz package falls under First-Class Package Service, which costs about $5.70. Since each Forever stamp is worth the current First-Class Mail letter rate (which is $0.66 as of 2023), you would need approximately 9 Forever stamps to cover the postage for a 12 oz package. Always check the latest postage rates for the most accurate calculation.