For those not in the know, these deals happen every February, June, and October.
FAQ:
Q: Does it work with preorders?
A: Yes. (And if your preorder is delayed, Sony will offer you a refund and you can keep the $15, too.)
Q: Does a PlayStation Plus sub count towards the $100?
A: Yes.
Q: If I load $100 of credit into my wallet, do I get the $15?
A: No. You have to spend $100 on something.
Q: Will $99.98 count?
A: Some people have reported that they just received their $15 automatically, others had to contact customer service to get it. Best advice is to buy a cheap avatar for about $0.50 to be on the safe side.
Q: Does it stack? If I spend $200, will I get $30 back?
A: No, you can only get $15 back; no more.