Grandpa and Viagra...

Grandpa found Viagra in his son's medicine cabinet. He asked if he could try one. The son said, "I don't know, they're very strong and expensive." "How much?" he asked. “$10 dollars a pill,” the son said. "I don't care. I'll try one, and leave the money under your pillow.” The next morning the son found $110.00 under h...is pillow. Grandpa, "I said each pill was $10.00, not $110.00. "I know, the $100 is from Grandma."