Solo me quedan veintinueve euros hasta el viernes, así que prefiero cocinar en casa.

Because Spanish often expresses this idea as what is left to me rather than what I have.

• Solo me quedan veintinueve euros literally means Only twenty-nine euros remain to me.
• A more direct version with tener would be Solo tengo veintinueve euros, which is also correct.

The version with quedar emphasizes that this is the amount you have left.

Here, quedar means to remain / to be left.

So:

• Me quedan veintinueve euros = I have twenty-nine euros left
• No me queda dinero = I have no money left
• Me queda una semana = I have one week left

It is a very common verb in Spanish for talking about what remains.

Because the verb agrees with veintinueve euros, which is plural.

In this structure, the thing that remains is the grammatical subject:

• Me queda un euro → singular
• Me quedan veintinueve euros → plural

Even though English says I have, Spanish is structured more like:

• One euro remains to me
• Twenty-nine euros remain to me

So the verb matches euros, not me.

Me means to me / for me.

So:

• Me quedan veintinueve euros literally = Twenty-nine euros remain to me

This indirect object pronoun shows who the remaining money belongs to.

Other examples:

• Te quedan dos días = You have two days left
• Nos queda pan = We have bread left

Yes, solo means only here, and its position is flexible.

• Solo me quedan veintinueve euros
• Me quedan solo veintinueve euros

Both are natural. Starting with solo gives a bit more emphasis to the limitation: I only have...

Also, in modern spelling, solo usually does not need an accent. Older texts may show sólo, but today solo is standard in most cases.

Here hasta el viernes means until Friday.

The idea is that the money has to last from now up to Friday.

So:

• Solo me quedan veintinueve euros hasta el viernes = I only have twenty-nine euros left until Friday

In context, it often implies to last me until Friday.

Así que means so / therefore. It introduces a consequence.

• Solo me quedan veintinueve euros..., así que prefiero cocinar en casa.
• I only have twenty-nine euros left..., so I prefer to cook at home.

By contrast, porque means because and introduces a reason.

Compare:

• Prefiero cocinar en casa porque solo me quedan veintinueve euros. = I prefer to cook at home because I only have twenty-nine euros left.

So:

• así que = result
• porque = reason

Because after preferir, Spanish normally uses an infinitive when the subject stays the same.

• Prefiero cocinar en casa = I prefer to cook at home

Just like in English: I prefer to cook, not I prefer I cook.

You would use a different structure if the subject changes:

• Prefiero que cocines tú = I prefer that you cook

So:

• same subject → preferir + infinitive
• different subject → often preferir que + subjunctive

En casa is the normal way to say at home or at my place / at home in general.

• Cocinar en casa = to cook at home

If you say en la casa, you are usually talking about a specific house as a physical building:

• Estoy en la casa de Ana = I’m in Ana’s house

So for the general idea of home, Spanish usually uses en casa without an article.

Yes. Numbers from veintiuno to veintinueve are normally written as one word:

• veintiuno
• veintidós
• veintitrés
• veintiséis
• veintinueve

Notice that some of them have written accents, but veintinueve does not.

From treinta onward, Spanish usually uses separate words with y:

• treinta y uno
• cuarenta y cinco

Yes, that is correct and natural.

Compare the nuance:

• Solo tengo veintinueve euros... = I only have twenty-nine euros...
• Solo me quedan veintinueve euros... = I only have twenty-nine euros left...

The version with me quedan sounds a bit more focused on what remains. The version with tengo is simpler and more direct.

Yes, it sounds natural in Spain.

A speaker from Spain would commonly say things like:

• Me quedan veinte euros
• Hasta el viernes
• Así que prefiero cocinar en casa

It is a normal, everyday sentence. If anything, me quedan is especially common and useful in real conversation when talking about time, money, food, battery, or anything that is left.

Yes, solo can mean both:

• only
• alone

In this sentence, it clearly means only:

• Solo me quedan veintinueve euros = I only have twenty-nine euros left

If it meant alone, the sentence would not make sense in context.

Examples:

• Estoy solo en casa = I am alone at home
• Solo tengo diez euros = I only have ten euros

Context usually makes the meaning clear.