Can you please check these sentences I'm doubtful about?

1) They will be extras in a sci-fi film. They’ll take a day off school and they will get paid, too.
2) The film director tells them they have to imagine living in the year 2050. At that time there will be aliens on earth and they will be very frightened of them.
3) At first they won’t see the aliens because they are going to create the real aliens using computer effects.
4) They will see Frank and Kate who will play the role of the aliens themselves.
5) One alien will offer them a piece of metal and Mickey will take it. Mickey is going to show the director how he will offer the alien a piece of metal.The director is going to rehearse quickly because it’s starting to rain.
6) I'll get some CDs for the party.
I'll move the furniture in the garage so that we can have more space to dance
7)I'll go to the supermarket and get the drinks. I'll help you carry the shopping.
8)Last Saturday I went out for a pizza with my friends/I went to a pizza-restaurant for dinner./I had dinner at a pizza-restaurant (are they all possible?)
9) I like eating out though I can't now because I have to scrimpe and save (?).I have to save (economize) on eating out (??)
Today's temperature is 20 degrees Centigrade.
The phone bill is 300 £

1) OK

2) The film director tells them they have to imagine living in the year 2050. At that time there will be aliens on earth and they will be very frightened of them. 2 commas needed

3) AOK

4) They will see Frank and Kate who will play the role of the aliens.

5) One alien will offer them<~~who are "them"? a piece of metal and Mickey will take it. Mickey is going to show the director how he will offer the alien a piece of metal. The director is going to rehearse quickly because it’s starting to rain. comma needed

6) I'll get some CDs for the party.
I'll move the furniture in the garage so that we can have more space to dance
period needed

7)I'll go to the supermarket and get the drinks. I'll help you carry them home.

8)Last Saturday I went out for a pizza with my friends/I went to a pizza-restaurant for dinner./I had dinner at a pizza-restaurant (are they all possible?) I'd say pizza house; everything else is fine.

9) I like eating out though I can't now because I have to scrimp and save. I have to save money by not eating out'

Today's temperature is 20 degrees Centigrade. or "20C"

The phone bill is 300 £
Put the sign for "pounds" before the number, not after. Same with the US dollar sign.

$100 = one hundred US dollars

£300 = three hundred pounds

1) The sentences look fine. They express that the characters will be extras in a sci-fi film, they will take a day off from school, and they will also get paid for their work.

2) The sentence appears to be grammatically correct. It states that the film director instructs the characters to imagine living in the year 2050, where aliens will be present on Earth, and the characters will be very frightened of them.

3) The sentence seems accurate. It suggests that initially, the characters will not see the real aliens because the aliens will be created using computer effects.

4) The sentence looks fine. It mentions that the characters will see Frank and Kate, who will be playing the role of the aliens themselves.

5) The sentence seems correct. It states that one of the aliens will offer the characters a piece of metal, and specifically mentions that Mickey will take it. Additionally, it mentions that Mickey will show the director how he plans to offer the alien a piece of metal, and the director will quickly rehearse because of the rain.

6) The sentences seem grammatically correct. The first sentence implies that you will obtain some CDs for the party. The second sentence suggests that you will rearrange the furniture in the garage to create more space for dancing.

7) The sentences appear to be accurate. The first sentence implies that you will go to the supermarket and purchase drinks. The second sentence indicates that you will assist in carrying the groceries.

8) All three options are possible and grammatically correct. They express that the speaker went out for a pizza with their friends or had dinner at a pizza-restaurant.

9) The first sentence seems accurate. It states that the speaker enjoys eating out, but cannot do so currently because they need to save money. The second sentence is also correct, as it explains that the speaker must economize by saving money on eating out.

10) The sentences seem to be correctly formatted. The first sentence states that the temperature today is 20 degrees Celsius. The second sentence suggests that the phone bill is £300.