I can understand the bit about the "special sale" being funny in context, but the two liner completely passed me by.
My extremely limited German translates "gespart" to "saved", and "Wochen" to "weeks". I'm guessing that the two liner actually translates into something like "Have you come? / Weeks ago", but I'm having trouble wrapping my head around it.
The scene is also funny because the person who mentions its on sale isn't attractive (at least, in my opinion) yet they're informed. Its a clever trick, given the goal was to prevent HIV spreading by promoting condom usage among the German people. I'm not even sure why I remember the commercial. Probably because I'm from a Dutch area where people watch a lot of German TV (not our household though).
With regard to the other quote: a man cannot save sperm for weeks, he'll have a wet dream eventually, after approx one week. So its either a straight up lie, an overstatement / white lie, someone who doesn't know such (though we don't know if the person asking knows such or sees through it), or its taken honestly and literally (he's saved up, but who knows how full the bucket is). Since we both have autism, I suppose we go for the last explanation.
I'm not even sure where its from. Probably some comedian.
Tina, was kosten die kondome? Tina replies: 3,99. To which a customer says: Nein, 2,99, sie sind in Sonderausverkauf.