Yes, it is yet another sale going live at 9:00 am PST. And while this one is for parking, make no mistake: it can be as much a bloodsport as a badge sale.
This would be for those highly-coveted parking garage spots under the convention center, and in various lots around town. Your dealer here is Ace Parking, and they are ready to sell to you. No, you can't drive blithely into San Diego and expect to easily score a spot anywhere during the Con. If you'd like to drive into town and park, it is smart to buy right now - and you will be buying from The Permit Store on 19 April at 9:00 am PST.
While the most desirable spots are right underneath the Con, there are other lots at various hotels, Petco Park, and so on. If you want to be strategic, consider a lot near a shuttle or trolley stop.
If you're new to Comic-Con, you may not have expected a pre-sale of parking spots, but by now you should be understanding that everything goes on sale in advance. Except for people who rent themselves out to stake your place in the Hall H line, which I think is a great idea for unemployed San Diegoans with an entrepreneurial spirit.