question: it is the most commonly used method on these "free giveaway", or "i'm quitting, free items" type sites.
Capitalize this past sentence correctly.
A: It is the most commonly used method on these "free giveaway", or "I'm quitting, free items" type sites.

question: transport is available on a 3500 kg purpose designed trailer.
Capitalize this past sentence correctly.
A: Transport is available on a 3500 kg purpose designed trailer.

question: this indian tribe had, as i mentioned earlier, very much
Capitalize this past sentence correctly.
A: This Indian tribe had, as I mentioned earlier, very much