"You merchants estimate the prices."

Translation: Vos mercatores pretia aestimatis.

[AdmJota]

Is "Vos" necessary here? I thought that with "Mercatores" in the nominative plural, "Mercatores pretia aestimatis." would be sufficient.

[IPSEDIXIT3]

Small correction: the 'mercatores' used here is actually the vocative pl. form, since the 2nd person pl. 'aestimatis' indicates direct address (with the 'vos' being emphatic). Note also that the mood isn't imperative (which would be ‘aestimate’) so its meaning is definitely not “You, merchants, estimate the prices.” I imagine a speaker at a merchant consortium claiming: you all [merely] estimate prices… ego autem ea scio.

[Moopish]

Mercatores pretia aestimatis was accepted for me.

[PERCE_NEIGE]

It shouldn't be accepted, as the "you" in English, as in Latin is really emphatic.
Translating "You, merchants, estimate the price" with "Mercatores pretia aestimatis", is absurd.
The meaning of the English sentence is lost, when it's easy to make the same emphasis in Latin.

[Ivitcyex]

Mercatores pretia aestimatis is fine I think. The you is required in English, not to be emphatic, but rather because the verb doesn't clarify the subject like the Latin does. There's a difference between [you merchants] and [you, merchants,...].

[Anastasia_Wolfe]

The Latin 'you' is there in 'aestimatis'. I can see both options with and without vos making contextual sense with the emphasis being 'you'.

[AdmJota]

Hmm. Perhaps I had some typo that I missed.