A good turn - favour.
A good turn - this phrase is usually used with 'do/did'.
Is it correct to say "We can get a good turn in return when we are in need."?
Can we use the word 'get'?
In principle, a good turn is an idiomatic expression in its own right, for example
one good turn deserves another. - proverb
In practice, it is usually used in the expression Do someone a good turn. This NGram shows how uncommon get/got a good turn is, and if you look at actual instances, none that I could find relate to this meaning.
The NGram also shows that the normal way of expressing receipt of a good turn is to say ... did me a good turn.
The more normal way of expressing can get a good turn would be that somebody owes me a favour. This NGram shows that owes me a good turn used to be common in the 1880's but in recent times owes me a favour is much more common.