Prefiero comprar productos ecológicos en el mercado de mi barrio.

In Spanish, when one verb directly follows another (and the first one expresses desire, plan, preference, etc.), the second verb is normally in the infinitive form.

• Prefiero comprar = I prefer to buy
  
  • prefiero = I prefer
  • comprar = to buy (infinitive)

If you said prefiero compro, you would literally be saying I prefer I buy, which is ungrammatical in Spanish. The pattern you want is:

• Prefiero + infinitive
  
  • Prefiero comer en casa. – I prefer to eat at home.
  • Prefiero leer. – I prefer to read.

Prefiero is the first person singular (yo) form of the verb preferir in the present indicative.

Conjugation (present indicative of preferir – e → ie stem change):

• yo prefiero
• tú prefieres
• él / ella / usted prefiere
• nosotros preferimos
• ustedes / ellos prefieren

So, because the subject is “I” (yo), you must use prefiero.

• Prefiere = he/she/you (formal) prefer(s)
• Prefiera would usually be a subjunctive form, not used here.

No. Preferir in this sentence is not reflexive, so you don’t use me.

• Me prefiero would literally mean I prefer myself, which doesn’t make sense in this context.

You want:

• Prefiero comprar productos ecológicos… – I prefer to buy organic/ecological products…

Use reflexive pronouns only when the action is done to oneself (like me levanto, me baño, me siento), not with preferir in this meaning.

Both are often understood as “organic products” in everyday speech, but there are some nuances:

• Productos orgánicos

  • Very common term in Latin America, especially for food that is certified organic (no synthetic pesticides, etc.)
  • You will see orgánico a lot on labels and in stores.

• Productos ecológicos

  • More frequent in Spain, although it is understood in Latin America.
  • Can sound a bit more general: products that are environmentally friendly, sustainable, etc.

In most everyday contexts in Latin America, if you mean certified organic food, productos orgánicos is the most natural. But productos ecológicos will still be understood as “environmentally friendly / organic-type products.”

In Spanish, most adjectives normally go after the noun, especially when they describe an essential characteristic:

• productos ecológicos – ecological products / organic products
• mercado local – local market
• comida mexicana – Mexican food

You can sometimes put adjectives before the noun, but that often adds a different nuance (emotional, poetic, or subjective) and is less neutral:

• pobres niños – poor children (emotionally, “those poor kids”)
• niños pobres – children who are poor (financially)

Here, ecológicos is a straightforward descriptive adjective, so productos ecológicos is the normal, neutral order.
Ecológicos productos sounds wrong or very marked/poetic.

Adjectives in Spanish must agree in gender and number with the noun they modify.

• productos is:
  • masculine (it ends in -o in the singular: el producto)
  • plural (more than one: los productos)

So the adjective ecológico has to match:

• singular masculine: ecológico – producto ecológico
• plural masculine: ecológicos – productos ecológicos
• singular feminine: ecológica – comida ecológica
• plural feminine: ecológicas – frutas ecológicas

It depends on the meaning:

• en el mercado = in/at the market (location)

  • Prefiero comprar… en el mercado = I prefer to buy… at the market.

• al mercado (a + el mercado) = to the market (movement, direction)

  • Voy al mercado. = I’m going to the market.

In your sentence, you are talking about where you prefer to buy (location), not going there, so en el mercado is correct.

No. In Spanish, you usually need the definite article (el, la, los, las) before singular countable nouns used in this kind of general, specific sense.

• ✅ en el mercado de mi barrio – at the market in my neighborhood
• ❌ en mercado de mi barrio

Without el, it sounds ungrammatical. The article el is required just like in:

• en la tienda, en el parque, en la escuela

Here, de mi barrio is working like “of my neighborhood”, describing which market you’re talking about:

• el mercado de mi barrio = the market of my neighborhood → my neighborhood market

If you said:

• en el mercado en mi barrio

it sounds like two separate pieces of information:
“at the market in my neighborhood” (which is still understandable, but less natural than el mercado de mi barrio).

Using de:

• el mercado de mi barrio – identifies that specific market that belongs to / serves / is associated with your neighborhood.
  De in Spanish often indicates a relationship like this (possession, belonging, origin).

Grammatically, yes: en el mercado de mi vecindario is correct and understandable.

Nuance:

• barrio

  • Very common word across the Spanish-speaking world.
  • Often means neighborhood, district, or area within a city.
  • In Latin America, barrio is the more natural everyday word for neighborhood in this kind of sentence.

• vecindario

  • Also means neighborhood, but is used less frequently in some regions.
  • You’ll still be understood, but barrio sounds more idiomatic in many Latin American contexts here.

So en el mercado de mi barrio is usually the more natural choice.

You need a direct object pronoun for los productos (masculine plural) → los.

You have two correct options for placement:

1. Attach it to the infinitive:

   • Prefiero comprarlos en el mercado de mi barrio.

2. Place it before the conjugated verb:

   • Los prefiero comprar en el mercado de mi barrio.

Both mean: I prefer to buy them at the market in my neighborhood.
The first option (prefiero comprarlos) is the most common and feels a bit more fluid.

You can use the conditional of preferir:

• Preferiría comprar productos ecológicos en el mercado de mi barrio.
  = I would rather buy / I would prefer to buy organic products at the market in my neighborhood.

Nuance:

• Prefiero comprar… – direct, present preference: I prefer to buy…
• Preferiría comprar… – a bit softer or more hypothetical: I’d rather buy / I would prefer to buy…, often used when comparing options or being more polite.