LORELAI: I just wanted to tell you how amazing you were tonight. Really, you completely came through for her.
CHRISTOPHER: She deserves it.
LORELAI: I haven’t always given you a lot of credit in the past, but I’m giving you credit now. Big credit. Major credit. Buy yourself a sofa.
Lorelai is referring to store promotions, common for big ticket items such as furniture, where credit is extended to approved customers so they can take their purchase home immediately.
The Annotated Gilmore Girls 