How much is 4 oz of butter?

A large knob. I think you know what that looks like. 

one quarter of a pound or about 113.4 grams.

Butter is sold by weight. There is 16oz to a pound, so it's typically 1/4 pound sticks.

We also have 'liquid' volume that uses 'fluid' ounces, or "floz".

The weight of 4oz of butter is approximately 4floz as well, not exact, but pretty close. There are 8floz in 1 cup, so 4floz is 1/2 cup or 8 tablespoons.

A QUARTER OF AN 16 OUNCE POUND:

1/4 lb , or about 134 grams .

Mass wise in metric  it is 125 g 

Usually butter comes 8 tablespoons to the stick. And since there are 2 tbsp. per oz., that's also 4 oz.

Answer:

1 stick of butter.

If you are asking how much it weighs, your question answers itself. If you are asking for the price, that should be written on the display, but maybe not very prominently. The kid at the check-out stand can tell you.

Are you asking about volume, weight, cost? 

4 oz is equal to 0.25 pounds of butter