LORELAI: Oh, hey. Where’ve you been? I thought Taylor auctioned you off to the highest bidder.
RORY: No, I just went to get some pizza and I, uh, wandered around the bookstore for a little while. Here. [hands her a book]
After the fundraiser, Jess took Rory out for pizza, as her picnic was inedible – a clear parallel to Luke bringing Lorelai diner food to replace her inadequate basket. They then wandered around Stars Hollow Books together. No doubt tongues were wagging in town over that.
Rory said it’s “tradition” to eat a picnic with the person who buys your basket, but sitting together on a secluded bridge for an hour, going for pizza, and then book shopping seems to be going above and beyond tradition. As Dean finds shopping for books boring and only goes with Rory so he can watch her, Rory would have enjoyed doing it with someone who shares her passion for reading.
Note that Lorelai makes the same joke about Rory being “auctioned off” that she made to Emily in regard to school dances.