the amount in one package(envelope)of custard mix
One heaping 1/4 cup.
One Envelope can make 2 Cups.
That will depend which country you are in, the destination of the envelope, and by which method you are mailing it.
The cost to mail a manila envelope will depend on the size of the envelope and the weight of the envelope. The average cost to mail a manila envelope that is 8"X11" is about $2 if the contents weigh less than one pound.
That is 4 tbsp
A 3-oz box of sweetened & flavored jello mix has the same amount of gelatin as one envelope (1 Tablespoon) of unflavored, unsweetened gelatin. 3 oz box jello mix = 1 envelope unflavored gelatin
The answer is an envelope. It contains a letter.
One
The word is "envelope" (which usually holds only one letter).
It can cost from one dollar up depending on what brand it is and the amount of it. I Hope that answered your question.
One first class stamp (depending on weight of course).
equal parts to mix