La carn que comprem avui té descompte.

Because carn is a feminine noun in Catalan, so it takes la in the singular: la carn.

A useful thing to notice is that carn is usually a mass noun, like meat in English. So Catalan normally keeps it in the singular when talking about meat in general:

• la carn = the meat
• m’agrada la carn = I like meat

So both the gender and the singular are normal here.

Here que is a relative pronoun, meaning that, which, or sometimes nothing at all in natural English.

So:

• La carn que comprem avui
  = The meat that we buy today = The meat we buy today

In Catalan, que is very commonly used to link a noun to extra information about it. It introduces the clause that describes la carn.

Comprem is the present indicative, 1st person plural form of comprar (to buy).

The verb forms are:

• jo compro = I buy
• tu compres = you buy
• ell/ella compra = he/she buys
• nosaltres comprem = we buy
• vosaltres compreu = you all buy
• ells/elles compren = they buy

So que comprem avui means that we buy today.

Because Catalan often drops subject pronouns when the verb ending already shows who the subject is.

Since comprem clearly means we buy, you do not need nosaltres.

So both are possible:

• que comprem avui
• que nosaltres comprem avui

But the version without nosaltres is more neutral and natural unless you want emphasis or contrast, for example:

• la carn que nosaltres comprem, no la que compren ells
  = the meat that we buy, not the one they buy

Avui means today, and its position is fairly flexible in Catalan. In this sentence, que comprem avui is a very natural word order.

It tells you when the buying happens.

You may also see other placements, depending on style or emphasis, such as:

• La carn que comprem avui té descompte.
• La carn que avui comprem té descompte.

The first version is the most neutral. The second sounds a bit more marked or literary.

Té is the 3rd person singular form of tenir (to have), meaning has.

So:

• la carn té descompte = the meat has a discount / is discounted

The accent matters because té and te are different words:

• té = has
• te = tea

The accent helps distinguish them in writing.

Because the subject is la carn, which is grammatically singular.

Even though meat can refer to a quantity of food, the noun itself is singular, so the verb must also be singular:

• La carn té descompte.
• not La carn tenen descompte.

This is similar to English:

• The meat has a discount
• not The meat have a discount

In Catalan, té descompte is a natural retail-style way to say that something has a discount or is on sale.

Leaving out the article makes it sound more general or categorical:

• té descompte = it is discounted / it has discount
• té un descompte = it has a discount (a more specific discount)

So:

• La carn que comprem avui té descompte
  suggests that the meat is discounted, without focusing on one particular discount amount.

If you wanted to mention a specific discount, then un descompte would be more likely:

• té un descompte del 20% = it has a 20% discount

It can often cover both ideas, depending on context.

Catalan simple present is quite flexible. Comprem can mean:

• we buy
• we are buying

So que comprem avui can naturally refer to the meat we buy today or we’re buying today, depending on the situation.

Catalan often uses the simple present where English might prefer either the simple present or the present continuous.

Yes. That is a very useful comparison.

Catalan normally keeps que in this kind of sentence:

• La carn que comprem avui...

But English often drops that:

• The meat that we buy today...
• The meat we buy today...

So when translating into English, you may or may not include that. In Catalan, though, que is the normal choice.