How many stamps do you put on from Utah to Idaho?

If you mean to send a letter, the rate is the same no matter where in the US you send it.-

45 cents for up to one ounces- 20 cents more for the second ounce- extra charges for letter that are thick and big envelopes.

If you want to send a package, the rate varies depending on the weight as well as the distance. The rates are complicated and if the package weighs a pound or more, you have to take it to the post office window and say what is in it.