I'm starting to think that Alan isn't as broke as he shows himself to be. Perhaps he's still squirelling away money for when he's an old man, like he was in an episode from an earlier season. Maybe he just enjoys mooching off Walden so much, that he's now a mooching addict. He gets Lyndsey to pay for most of the stuff when they're on a date.
That'd be good for an episode, Jake,Walden are discussing Alan;
Walden: Alan, seems to have made it a habit of mooching.
Jake: Maybe, my dad should check into "Moocher's Anonymous".
Berta: Oh, yeah, I can just it now. Zippy stepping up in front of everyone saying,"Hi, my name is Alan Harper and I have a mooching problem."
They'd all laugh and Alan would overhear them and say that is not true. He'd tell Lyndsey what they said about him while he's on a date with her and say to her that is ridiculous. Lyndsey would SARCASTICALLY agree with Alan. Then when the check for their dinner comes, Alan would ask Lydnsey if she could pay for dinner because he forgot his wallet. Lyndsey would give Alan an angry look. We'd then see a banner saying, "Moocher's Anonymous" and then we'd see Alan stepping in front of it with Lyndsey with him.
Alan: Hi, my name is Alan Harper....(Lyndsey elbows him in side, hard) OW! And I...have a mooching problem."