PSN cards come in $30 and $50 here in Australia, and most GAME and EB Games carry them. Go to their respective websites, look at their store locater and give them a call to see if they have them in stock
Its been really funny with GAME lately, not getting any for months and months, but the one I work at has them now and gets them regularly so most other places should be good now
The only place to sell them is JB Hifi because they generate a code for you on the receipt. When the codes got comprmised in the hacks SONY didtched the awesome $30 / $50 + free Blu-Ray case system ******* hackers!
i thinks its like over kill getting a 50$ card just to buy a 18$ dlc, my dad is such a tight a$$ and wont buy the gt5 dlc again for my account but maybe now i can say wellll its that or give me 50$ haha