Hi ha un descompte en la verdura avui.

Hi ha is the standard Catalan way to say there is or there are.

• ha comes from the verb haver
• hi is an old locative element that stays in this expression

So it is best to learn hi ha as one fixed chunk meaning there is / there are, rather than trying to translate hi separately every time.

Because descompte is a masculine singular noun in Catalan.

That means it takes:

• un = masculine singular indefinite article

So:

• un descompte = a discount

If the noun were feminine, you would use una instead.

In Catalan, verdura is often a collective noun. It refers to vegetables as a category, like vegetables or produce in English.

So even though English often uses a plural noun, Catalan commonly uses singular:

• la verdura = vegetables / produce

This is very normal and natural.

Catalan uses the definite article more often than English does.

Here, la verdura refers to:

• vegetables as a general product category
• the vegetable section / vegetable produce in a shop context

So even if English might just say on vegetables, Catalan naturally says en la verdura.

Here en means something like on or for in the sense of a discount on vegetables.

With descompte, Catalan often uses:

• descompte en + producte = discount on a product/category

Compare:

• un descompte en la verdura = a discount on vegetables
• un descompte del 20% = a 20% discount

So en introduces the thing that has the discount, while de/del often introduces the amount of the discount.

Yes. Avui is flexible.

These are all possible:

• Hi ha un descompte en la verdura avui.
• Avui hi ha un descompte en la verdura.

The second version is often slightly more natural if you want to emphasize today first.

Putting avui at the end is still perfectly understandable and natural.

Not exactly.

• descompte = a discount, a reduction in price
• oferta = an offer, a special deal, a sale item

So:

• Hi ha un descompte en la verdura avui focuses on the price being reduced
• Hi ha una oferta en la verdura avui sounds more like there is a special promotion

In everyday shop language, both can appear, depending on what the speaker wants to emphasize.

Yes, but the effect changes a little.

• Hi ha un descompte... sounds like a full, neutral sentence
• Hi ha descompte... sounds more concise, a bit like shop or advertising language

So for a learner, Hi ha un descompte en la verdura avui is the safest full version.

Yes, it is understandable and correct.

A native speaker might also say:

• Avui hi ha un descompte en la verdura.
• La verdura està d'oferta avui.

But your sentence works well and sounds like normal everyday Catalan, especially in a shopping context.

Usually yes in this kind of sentence, but the feeling can be slightly broader or more category-like.

Verdura often refers to:

• vegetables
• greens
• vegetable produce in general

So in a supermarket or market context, la verdura is a very natural way to refer to the vegetable category.