Remember that en means some, as in J’en ai. To specify just how much you have, you can add a quantity after the verb.
Tu as des timbres ? Oui, j’en ai dix.
Do you have any stamps? Yes, I have ten.
Ma sœur économise de l’argent, mais mon frère en dépense beaucoup.
My sister saves money, but my brother spends a lot of it.
Tu as beaucoup de chaussures parce que tu en achètes trop !
You have a lot of shoes because you buy too many!
Heads up that un autre can be either masculine or feminine!
To say that you have a certain value of paper bills, you’ll use billet de + value. To say that you have a certain value of coin, you’ll say pièce de + value.
Tu as des billets de cinq euros ?
Do you have any five‑euro bills?
Je cherche une pièce de cinquante centimes.
I’m looking for a fifty‑cent coin.