all of

1 The phrase all of is used in front of numbers in the sense of only, but is much more emphatic and expressive. 

It's used when the speaker wants to make an already small number sound really small.

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Note that although both all [ɑːɫ] and of [ǝːv] are theoretically long words, this phrase is short and unstressed [ɑlǝv]... almost like olive.

Nina feels terrible about getting coffee on her friend's shirt, but Natasha really doesn't care because it was so cheap. Here, she emphasizes just how little she paid for the shirt by making the price sound really small with all of.

Nina accidentally spills coffee on Natasha’s shirt.

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Nina: Oh no! I’m so sorry! Your beautiful shirt!

Natasha: Oh don’t worry — it’ll wash out.

Nina: I feel horrible! If it doesn’t come out, please let me know and I’ll pay you for it. 

Natasha: Oh please… I paid all of five bucks for this shirt at a thrift store.

_______________⦿ thrift store | A store that sells secondhand clothes.

Alex plays Boris a recording of his godson playing the piano.

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Alex: Boris, listen to this.

Boris: Nice. Someone you know?

Alex: My godson. 

Boris: I didn't know you had a godson. Is he a concert pianist?

Alex: I think he's a genius. He plays the piano, speaks three languages, his oil paintings have sold in galleries... and he's all of ten years old!

2 Conversely, all of can be used to emphasize what the speaker considers a high number. In this usage, it doesn't have a meaning of only, obviously, but rather of AS MANY AS -or- A WHOLE [number]. 

For instance, in the snippet below, Natasha's mad at her sister because she had sent her A WHOLE TEN messages and never heard back.

Natasha called her sister, Nina, two hours ago to invite her to meet up at the mall for some shopping and Nina agreed to go. However, she's running really late, and Natasha's starting to get annoyed.

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Nina: Sorry I'm late — parking was an absolute nightmare.

Natasha: Whatever...

Nina: What, so now you're pissed? Give me a little more notice next time.

Natasha: More notice? I've been calling you since yesterday. You don't pick up. I've left you all of ten messages!

Nina: [Looking at her phone] Ugh, sorry, Natasha — I accidentally left my phone on silent. 

_______________⦿ Whatever... | A snarky expression that lets the listener know that you don't believe them, out of anger, frustration, impatience, etc.⦿ pissed | Short for pissed off in the sense of being angry.⦿ Give me a little more notice next time. | Next time, tell me about something well in advance, instead of calling me right before.

Nina and Boris check into a cheap motel late one night during a long-distance drive. As she comes out of the bathroom, he realizes that she's not at all happy with the room.

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Boris: Baaaabe, I know it's not the Taj Mahal, but it's just for one night. I can't drive one more mile. My eyes are closing.

Nina: Well, I’m not staying in this fleabag one second longer. I just saw all of eight roaches in the bathroom — and even they were throwing up! Grab your shit and let’s find another place to stay. I'll gladly drive if you're too tired!

____________⦿ My eyes are closing. | I'm so sleepy, I can't keep my eyes open.⦿ fleabag | Literally, a bag of fleas, referring to a filthy hotel, house or apartment.⦿ your shit | vulgar: your things. This has nothing to do with the quality of his things — it's just another way of referring to things in general.