Learn Hardcore French: Pour ce voyage, une petite somme suffit si on partage les frais. - For this trip, a small amount is enough if we share the costs.

ce voyage = this/that trip (masculine singular, consonant sound)
cet is used before masculine nouns starting with a vowel sound: cet homme, cet avion
cette is used with feminine nouns: cette voiture, cette journée

You can’t say cet voyage or cette voyage because voyage is masculine and starts with a consonant sound, so only ce is correct here.

Why is it une petite somme and not un petit somme?

Somme (meaning amount / sum in a money context) is feminine in French, so it uses:

the feminine article une
the feminine form of the adjective petite

So you must say une petite somme.

Un petit somme would only be correct if somme were masculine, which it isn’t in this meaning. (There is also a colloquial masculine un somme = a nap, but that’s a different word and meaning.)

Why is the verb suffit singular? Shouldn’t it be plural because of les frais?

The subject of the verb suffit is une petite somme, which is singular.

une petite somme (subject)
suffit (3rd person singular of suffire)

Les frais belongs to the clause si on partage les frais. It’s not the subject of suffit; it’s just part of the condition. So the verb agrees with une petite somme, and singular suffit is correct.

What is the difference between suffire and saying être suffisant, and why use suffit here?

Both can express the idea of “being enough,” but suffire is more direct and idiomatic in this kind of sentence.

Une petite somme suffit. = A small amount is enough. (natural)
Une petite somme est suffisante. = A small amount is sufficient. (correct but sounds more formal / heavier)

In everyday French, suffire is usually preferred for this type of statement. Être suffisant(e) tends to sound more formal, technical, or written.

Could we say il suffit d’une petite somme instead of une petite somme suffit?

Yes, that’s also correct, but the structure and focus are a bit different:

Une petite somme suffit.
- Normal subject–verb order.
- Focus on a small amount as the subject.
Il suffit d’une petite somme.
- Impersonal il (dummy subject) + suffit de + nom.
- Very common pattern: il suffit de + noun / infinitive.
- Slightly more neutral/impersonal in tone.

Both mean essentially the same thing in this context.

Why is on used in si on partage les frais instead of nous?

In modern spoken French, on is very commonly used instead of nous to mean we. It is:

more informal and more frequent in everyday speech
conjugated like il/elle (3rd person singular): on partage

So:

si on partage les frais = if we share the costs (natural, everyday French)
si nous partageons les frais = if we share the costs (more formal / written or careful speech)

Both are grammatically correct; on just sounds more colloquial and common.

The English translation might use the future (like will be enough). Why is French using the present tense suffit and partage here?

French often uses the present tense where English would use the future, especially in conditional sentences and general statements.

Here, Pour ce voyage, une petite somme suffit si on partage les frais can refer to:

a general rule or fact about this trip
a future plan that’s presented as something settled or obvious

You could also say Une petite somme suffira si on partage les frais to clearly emphasize a future result, but the present tense is perfectly natural and common, especially if the speaker is presenting it as a general condition.

Why is it si on partage les frais and not something like si on partage des frais or si on partage aux frais? Does partager need a preposition?

Partager takes a direct object in French; it does not use a preposition here.

partager quelque chose = to share something
partager les frais = to share the costs/expenses

You do not say partager aux frais or partager des frais in this sense.
Des frais would sound like “some (unspecified) expenses,” but in this context we’re talking about the costs of the trip (all the costs), so les frais is more natural.

Why is it les frais and not just frais without an article, or des frais?

French almost always needs an article before a noun, and the choice of article changes the meaning:

les frais: the expenses/costs (here, the known or implied costs of this trip) – this is the natural choice
des frais: (some) expenses, an indefinite set of expenses (more vague)
Bare frais (no article) is generally not used in this meaning in standard French.

Since you’re referring to the specific expenses linked to this trip, les frais is the most idiomatic.

What exactly does frais mean here, and how is it different from coûts or dépenses?

In this context, frais means expenses / costs, especially practical, itemized costs like transport, accommodation, etc.

Rough nuances:

les frais: fairly standard term for expenses, used in many fixed expressions (e.g. frais de voyage, frais de port)
les coûts: more general word for costs, often used in economic or technical contexts
les dépenses: spending / outgoings / expenditures, focusing on the act of spending money

Here, les frais fits naturally because you’re talking about the expenses associated with a specific trip.

Why does the sentence start with Pour ce voyage? Could we put it later, like Une petite somme suffit pour ce voyage si on partage les frais?

Yes, you can move pour ce voyage without changing the basic meaning:

Pour ce voyage, une petite somme suffit si on partage les frais.
Une petite somme suffit pour ce voyage si on partage les frais.

Putting Pour ce voyage at the beginning:

sets the context right away (we’re talking about this trip)
slightly emphasizes the contrast with other possible trips (for this one, a small amount is enough)

Both word orders are grammatically correct and natural.

Should there be a comma before si? I often see commas before if in English.

In French, you usually do not put a comma before si when it introduces a condition, especially in a simple sentence like this.

Une petite somme suffit si on partage les frais. (standard)
Adding a comma (… suffit, si on partage les frais) is possible but tends to change the rhythm and is less common in neutral prose.

So the version without a comma before si is the normal, recommended punctuation.