HAVING EXTREME TROUBLE WITH THESE SENTENCES PLEASE

Could you please help me correct these sentences please?

1 It's going to cost you half the price it would cost you if you bought it here.

2 You're better off doing stuff that aren't necessary and end up not needing them than the other way around.

3 Having a phone is the rooms is the minimum criteria to get two stars for your hotel.

4 If the period/dates (looking at a computer screen) covers the date/period on/during which you will be here, then we will pay for you stay.

5 We'll go faster if we split the work/workload up amongst us.

6 Are you high up or can you walk up the stairs. What floor are you on?

7 We finished before the printer was done printing all the pages.

8 Put the address in the blank/where it's blank.

Thank you