Moving out

Sam walks into his bedroom and sees Karen packing a suitcase. 

Sam asks, "What are you doing?" 

Karen answers, "I'm moving to London! I heard that prostitutes there get paid £400.00 for what I'm doing 
for YOU for FREE!" 

Later that night, on her way out, Karen walks into the bedroom and sees Sam packing his suitcase.

Karen asks Sam where he's going, he replies, 

"I'm coming too. I want to see how you live on 
£800.00 a year."

Thanks Norman