Mañana compraremos salmón y pavo en el mercado para tener comida para toda la semana.

No, mañana does not have to go first. It is placed at the beginning here to set the time clearly: tomorrow.

Spanish word order is fairly flexible, especially with time expressions. You could also say:

• Compraremos salmón y pavo mañana...
• En el mercado compraremos salmón y pavo mañana...

But starting with mañana sounds very natural because it immediately tells the listener when the action will happen.

Compraremos is the simple future tense of comprar.

It means we will buy.

The ending -emos here is part of the future form for nosotros/nosotras. For regular -ar, -er, and -ir verbs, the future is formed by adding endings to the full infinitive:

• comprar → compraré, comprarás, comprará, compraremos, compraréis, comprarán

So:

• compraremos = we will buy

Yes. Vamos a comprar is also correct and very common in everyday Spanish.

So you could say:

• Mañana compraremos salmón y pavo...
• Mañana vamos a comprar salmón y pavo...

Both mean basically the same thing. The difference is mostly style:

• compraremos = simple future; slightly more concise, sometimes a bit more formal or neutral
• vamos a comprar = very common in speech, often feels a bit more immediate or conversational

In Spain, both are used a lot.

Because here salmón and pavo are being used as uncountable food items in a general shopping sense.

In Spanish, when talking about buying, eating, or wanting some amount of a food, it is very common to use the noun without an article:

• Comprar pan
• Comer arroz
• Necesitamos leche
• Voy a comprar salmón

If you said el salmón or el pavo, it would usually sound more specific, like a particular salmon or turkey already known in the context.

So in this sentence, no article sounds most natural.

Here it means turkey, the food.

But pavo can have other meanings depending on context. In Spain, in informal speech, it can also refer to a guy or even money in some expressions. However, in a sentence about buying food in the market, pavo is clearly the meat.

Because en means in or at, and here the sentence is saying where the buying will happen: at the market.

• en el mercado = at/in the market

If you wanted to express movement to the market, you would normally use al mercado:

• Mañana iremos al mercado = Tomorrow we’ll go to the market

Also, note that a + el = al. So a el mercado is incorrect; it contracts to al mercado.

Para often means in order to or for, and when it is followed by an infinitive, it expresses purpose.

So:

• para tener comida = to have food / in order to have food

The structure is:

• para + infinitive

Examples:

• Estudio para aprender.
• Voy al supermercado para comprar fruta.
• Compramos salmón y pavo para tener comida...

It explains why they are buying the food.

Because the idea is not simply to eat, but to have food available for the whole week.

Compare:

• para comer toda la semana = to eat all week / in order to eat all week
• para tener comida para toda la semana = to have food for the whole week

The actual sentence emphasizes having enough food stored or ready, not just the act of eating.

Because the two para phrases do different jobs.

1. para tener comida = expresses purpose

   • in order to have food

2. para toda la semana = expresses duration/coverage

   • for the whole week

So even though the same word appears twice, the meaning is not repetitive in a bad way. It is completely natural Spanish.

Because in Spanish, expressions like all the week, all the day, all the month usually take the definite article:

• toda la semana
• todo el día
• todo el mes
• todo el año

So toda la semana is the normal way to say the whole week or all week.

Because toda has to agree with semana, which is a feminine singular noun.

Agreement in Spanish:

• todo → masculine singular
• toda → feminine singular
• todos → masculine plural
• todas → feminine plural

Since semana is feminine singular, the correct form is:

• toda la semana

It can mean either, depending on context.

In Spain, mercado often refers to a food market, which may be:

• an indoor market hall
• a traditional local market
• sometimes an open-air market, depending on the situation

If someone meant a supermarket, they would usually say supermercado, not mercado.

Yes, you could say pavo y salmón. Grammatically, both are fine.

The order may depend on:

• what sounds more natural to the speaker
• which item they want to emphasize first
• habit or rhythm

So:

• salmón y pavo
• pavo y salmón

Both are correct.

Because Spanish often drops subject pronouns when the verb already makes the subject clear.

Here, compraremos already tells us the subject is we because of the verb ending.

So Spanish normally prefers:

• Compraremos salmón y pavo...

rather than:

• Nosotros compraremos salmón y pavo...

You can add nosotros if you want contrast or emphasis, but it is not necessary.

The original sentence already sounds natural, but in casual speech people might also say:

• Mañana vamos a comprar salmón y pavo en el mercado para tener comida para toda la semana.

That version may feel slightly more conversational because ir a + infinitive is very common in spoken Spanish.

Still, compraremos is perfectly natural and correct.