لدي عشرة دولارات.

In Arabic, possession is often expressed without a separate verb to have.

• لدى means something like with / in the possession of
• -ي means me / my

So لدي literally means with me or in my possession, and that is a normal Arabic way to say I have.

So the structure is not I have X as a verb sentence, but more like With me, there are X.

It is usually pronounced ladayya.

A useful breakdown is:

• لدى = ladā
• لدي = ladayya

That doubled y sound is important.

If you are reading the whole sentence in a simple classroom style, you can say:

ladayya ʿashara dūlārāt

If you are studying full case endings, a careful reading is:

ladayya ʿasharatu dūlārātin

Because with the numbers 3–10, Arabic uses gender polarity: the number takes the opposite gender of the counted noun.

• دولار is masculine
• so the number must use the feminine-looking form عشرة

That is why you get:

• عشرة دولارات = ten dollars

If the counted noun were feminine, you would use عشر instead.

Because after the numbers 3–10, the counted noun is normally plural in Arabic.

So:

• three dollars → ثلاثة دولارات
• ten dollars → عشرة دولارات

This is different from some other numbers in Arabic. For example, with 11 and higher numbers like 20, the noun is often singular:

• أحد عشر دولارًا
• عشرون دولارًا

So plural after 3–10 is the rule you are seeing here.

Because -ات is not used only for naturally feminine nouns.

In Arabic, many:

• non-human nouns
• borrowed words
• modern loanwords

can form their plural with -ات.

So دولار → دولارات is normal.

That does not make دولار feminine. The singular noun is still treated as masculine, which is why the number is عشرة, not عشر.

After numbers 3–10, the counted noun is normally genitive plural.

So in full vowelled form, it would be:

• دولاراتٍ

That is why a fully vowelled version of the sentence is often written as:

لَدَيَّ عَشَرَةُ دُولَارَاتٍ

A learner-friendly summary:

• عشرة = the number
• دولاراتٍ = plural, genitive

In ordinary Arabic writing, the short vowels and case endings are usually not written, so you normally just see لدي عشرة دولارات.

Yes, absolutely.

Both لدي and عندي can mean I have.

A rough difference is:

• عندي = very common, natural, often more conversational
• لدي = a bit more formal or written

So both are correct in Modern Standard Arabic, but لدي may sound slightly more formal.

No.

You do not need أنا, because the ending -ي in لدي already tells you that the meaning is I/me.

So:

• لدي عشرة دولارات = perfectly complete

You would add أنا only for emphasis or contrast, for example:

أنا لدي عشرة دولارات، وأنت لديك خمسة.

That means something like I have ten dollars, and you have five.

Because the phrase means ten dollars in a general, indefinite sense, not the ten dollars.

In Arabic, after numbers, the counted noun is usually indefinite unless you specifically mean a definite set.

So:

• عشرة دولارات = ten dollars
• الدولارات العشر or similar definite wording = the ten dollars

In your sentence, the speaker just means an amount of money, so دولارات is indefinite.