Compré un par de botas.

Compré is the first-person singular preterite of comprar.

• compré = I bought
• It is used for a completed action in the past.

In Spain, the pretérito indefinido (usually called the preterite in English-learning contexts) is very common for actions seen as finished:

• Compré un par de botas. = a finished past action

A learner often compares it with compraba:

• compré = I bought / I did buy
• compraba = I was buying / I used to buy

So in this sentence, compré is the natural choice because it refers to one completed purchase.

In Spanish, subject pronouns are often left out because the verb ending already shows who is doing the action.

• compré already tells you the subject is I
• So yo compré is possible, but usually unnecessary

You would include yo only for emphasis, contrast, or clarity:

• Yo compré un par de botas, no Marta.
  = I bought a pair of boots, not Marta.

Without emphasis, Compré un par de botas sounds completely natural.

Un par de means a pair of.

It is used for things that normally come in twos, such as:

• un par de botas = a pair of boots
• un par de zapatos = a pair of shoes
• un par de guantes = a pair of gloves

It can also sometimes mean a couple of in other contexts:

• un par de días = a couple of days

But with botas, it clearly means one pair.

Because in Spanish, after un par de, the noun normally stays plural.

So you say:

• un par de botas
• un par de zapatos
• un par de calcetines

This is the same idea as in English: a pair of boots, not a pair of boot.

Even though par is singular, it refers to two items, so the noun after de is plural.

Because par is followed by de when it links to the thing being counted or grouped.

So the pattern is:

• un par de + plural noun

Examples:

• un par de botas
• un par de guantes
• un par de pendientes

You cannot normally say un par botas. The de is required.

Compré is pronounced roughly kom-PREH.

A few key points:

• The final -é carries the stress
• The written accent mark tells you to stress that syllable
• The r in compré is a single Spanish r, not a strong rolled rr

So the stress pattern is:

• com-PRÉ

That accent is important because it helps distinguish forms and pronunciation.

Yes. Me compré un par de botas is also very common.

It usually suggests I bought myself a pair of boots.

So:

• Compré un par de botas = I bought a pair of boots
• Me compré un par de botas = I bought myself a pair of boots

In many everyday situations, especially when talking about clothes or personal items, Spanish often uses this reflexive form. It can sound very natural in conversation.

Not exactly.

• Compré unas botas = I bought some boots / a pair of boots
• Compré un par de botas = I bought a pair of boots

In practice, unas botas often implies one pair, because boots normally come as a pair. But un par de botas is more explicit and precise.

So if you want to clearly say one pair, un par de botas is better.

The word order is very standard and natural:

• Compré = verb
• un par de botas = direct object

Spanish often allows flexible word order, but this is the most neutral version.

You could say Yo compré un par de botas for emphasis, but the basic sentence is already perfectly natural.

Yes, this sentence is normal and correct across the Spanish-speaking world.

The main difference you might notice is not in the sentence itself, but in how often speakers choose one past tense or another depending on region. In Spain, for very recent past actions, people often also use the present perfect in some contexts:

• He comprado un par de botas.

But Compré un par de botas is still completely correct and widely understood everywhere.