"This is a bad price."
Translation:Este es un mal precio.
".....un precio malO" would be grammatically correct (because "malo" drops its "o" only before a masc. sing. noun). You could try that next time if you can access that sentence again. I don't know, but there may be something about the meaning of this sentence that disallows your suggested word order.
Mal is something called an "apócope" which is when a sound is dropped. In this case "malo" without the o at the end. Also "mal" is being used here as an adjective rather than an adverb. Usually in Spanish the adjective comes after the noun, but if you put "mal" at the end of a sentence it USUALLY changes from adjective to adverb.
Ex (adverb): Este es un precio mal puesto. (This is a price wrongly put) Yo conduzco mal. (I drive badly.) Lo estás haciendo mal. (You're doing it wrong.)
Ex (adjective): La mala suerte. (The bad luck.) El mal hablar no es bueno. (Wrong-talking is not good.)
I tried "un precio malo" and it was rejected.02/02/2019 ..reported it !
Esto is a demonstrative pronoun, but it is only used to refer to neuter, unknown or abstract concepts (e.g. when there is no specific noun acting as its antecedent so that you would know the gender of the noun).
Este can be either a demonstrative pronoun (this one or this masculine thing) or demonstrative adjective (this masculine noun). Its antecendent or the noun that it modifies, if an adjective, must be masculine.
This refers to a masculine noun (el precio), so you write Este.
Duo often marks correct answers incorrectly if they are teaching a new rule. In this case, "..mal precio" is the only correct answer because they are teaching that malo/bueno can be put before the noun if you drop the -o. So mal precio is the only correct answer
what makes you think that? if that were the case they should give prior warning. Additionally, why do they later frequently accept what has been reported by the users. it must be that their data base at a particular point in time is incomplete. I would guess this is the case here.
I think it would be este which refers to precio i.e. it could be written - this price is bad. este precio etc. If the sentence read - this is bad it would be esto es etc.
Well, I know that este in refers to precio is correct. My question is whether using esto would also be correct?