La grataĵo ne havas efikon sur la prezon.

Grataĵo is a noun built from:

• grat- = the root related to grati (to scratch)
• -aĵ- = a suffix meaning a concrete thing, result, or manifestation
• -o = noun ending

So grataĵo means a scratch, especially the visible mark or result of scratching.

In Esperanto, ne usually goes directly before the word or phrase it negates.

Here it negates the verb phrase:

• ne havas = does not have

So La grataĵo ne havas efikon... means the scratch does not have an effect.

The -n marks the direct object.

The verb havi means to have, and the thing that is had takes -n:

• havas efikon = has an effect

So efikon is in the accusative because it is the object of havas.

This is a very common learner question.

Normally, a preposition is followed by a noun without -n. But with some prepositions, especially location-type ones like sur, Esperanto can use -n to show direction, target, or something affected.

In the expression efiko sur la prezon, the idea is effect on/upon the price—the price is the target of the effect.

So this is a standard abstract use of the accusative after sur.

A good phrase to remember is:

• efiko sur ion = effect on something

Because Esperanto commonly says:

• efiko sur = effect on

Even though sur often literally means on, it is also used in abstract expressions such as influence, impact, or effect.

So here sur la prezon is the normal way to express on the price.

La is the definite article, meaning roughly the.

• la grataĵo = a specific scratch already known from context
• la prezon = a specific price, again known from context

But efikon has no article because it means an effect in a general/indefinite sense.

Esperanto has no separate word for English a/an, so a bare noun can often mean a/an.

Yes. Esperanto word order is fairly flexible because endings show grammatical roles.

This sentence uses a neutral order:

• La grataĵo ne havas efikon sur la prezon.

But other orders are possible for emphasis, for example:

• Sur la prezon la grataĵo ne havas efikon.

That gives extra emphasis to sur la prezon. The original version is the most straightforward and natural.

It is pronounced roughly gra-TA-zho.

A few helpful points:

• Stress in Esperanto is always on the second-to-last syllable
• grataĵo has the stress on TA
• ĵ sounds like the s in measure or vision

So:

• gra-TA-ĵo

Yes. Esperanto often allows both styles.

For example, a similar idea could be expressed with:

• La grataĵo ne influas la prezon.

That means roughly The scratch does not influence the price.

The version with havas efikon is perfectly natural; it is just a noun-based expression rather than a single-verb one.