Local Train ticket from Songjiang south railway station to Shanghai Hongqiao airport

Do you mean subway train or railway train here?

Anyway, for railway train, you can just purchase the tickets when you arriving at the station.
Take the bullet train to get to Hongqiao Railway Station first. Duration is ajust 14 minutes. The ticket fare of first class seat is CNY 22.5 and second class seat is CNY 13.5. Then walk for about 10 minutes to the airport via an underground passage or take subway line 10 to arrive at the airport. The subway ticket fare is CNY 3 per person.

For subway train, take subway line 9 from Songjiang South, get off at Yishan Road. Then transfer to line 3 to Hongqiao Road Station and line 10 to Hongqiao Airport.
It costs CNY 7 per person. The duration is about 75 mins. The ticket can be got upon arrival. so no worry:)