Sense cap targeta, només pots pagar en efectiu.

Both are possible, but they are slightly different in feel.

• sense targeta = without a card
• sense cap targeta = without any card at all

Adding cap makes it more explicit and a bit stronger. It suggests not even one card.

Also, Catalan often leaves out the article after sense when speaking generally:

• sense diners = without money
• sense cotxe = without a car
• sense targeta = without a card

If you said sense la targeta, that would usually mean without the specific card.

Yes. Cap has more than one meaning.

In Catalan:

• cap can mean head
• cap can also mean any / no

Here it is clearly the second meaning, because it appears in sense cap targeta.

Compare:

• Em fa mal el cap = My head hurts
• No tinc cap problema = I have no problem
• Sense cap targeta = Without any card

So this is just a case of one word having multiple meanings.

Catalan usually drops subject pronouns when the verb already makes the subject clear.

Here, pots already tells you the subject is you singular:

• pots = you can

So tu is not necessary.

You could say:

• Sense cap targeta, tu només pots pagar en efectiu

But that would add emphasis, as if contrasting you with someone else. In normal Catalan, leaving out tu is more natural.

Because poder works like a modal verb, just like can in English.

Structure:

• pots = you can
• pagar = pay

So:

• pots pagar = you can pay

This is very common in Catalan:

• vull menjar = I want to eat
• he de marxar = I have to leave
• pots pagar = you can pay

The first verb is conjugated, and the second stays in the infinitive.

Because només usually goes before the part it limits.

Here:

• només pots pagar en efectiu

This means the limitation applies to the whole action: the only thing you can do is pay in cash.

Catalan is somewhat flexible, but placement changes the emphasis a little:

• Només pots pagar en efectiu = You can only pay in cash
• Pots pagar només en efectiu = You can pay only in cash

Both are understandable, but the first version is very natural and common.

Because en efectiu is the normal fixed expression for in cash.

It works like an idiomatic payment expression:

• pagar en efectiu = pay in cash
• pagar amb targeta = pay by card / with a card

So Catalan uses different prepositions in different payment expressions:

• en efectiu
• amb targeta

You should learn en efectiu as a set phrase.

On its own, targeta just means card. The exact type depends on context.

In a payment sentence like this, people will usually understand it as a bank card, such as:

• targeta de crèdit = credit card
• targeta de dèbit = debit card

If the speaker wanted to be more precise, they could say one of those longer forms. But in everyday use, targeta is often enough when the context is payment.

Yes.

pots is the 2nd person singular form of poder, so it means you can when speaking to one person informally.

Related forms:

• pots = you can (singular informal)
• pot = you can (formal singular, or he/she/it can)
• podeu = you can (plural, or singular formal in some varieties)

So if a sign wanted to address everyone more impersonally, Catalan might also use:

• només es pot pagar en efectiu = payment can only be made in cash

It is placed first to set the condition right away.

So the sentence is structured like:

• Without any card, ...
• you can only pay in cash.

This is very natural in Catalan. Putting that phrase first helps the listener immediately understand the situation before hearing the main statement.

You could move it:

• Només pots pagar en efectiu sense cap targeta

But that version is less natural in many contexts, and it delays important information. The original order is clearer and smoother.

Yes. Catalan often uses impersonal phrasing, especially on signs, notices, and instructions.

For example:

• Sense cap targeta, només es pot pagar en efectiu = Without any card, payment can only be made in cash
• Només s’accepta efectiu = Only cash is accepted

The original sentence speaks directly to the reader:

• només pots pagar... = you can only pay...

That is also perfectly natural, just a little more direct.

It is the most common everyday one, yes.

Other possibilities exist, such as solament, but només is the usual word in normal speech and writing.

Examples:

• Només tinc cinc euros = I only have five euros
• Només pots entrar amb reserva = You can only enter with a reservation

So in this sentence, només is exactly the normal choice.