The blind salesman

[asperity]

A woman goes into Discount Fishing Supplies to buy a rod and reel for her grandson's birthday.  She doesn't know which one to get, so she just picks one and goes over to the
counter.  The salesman is standing there, wearing dark glasses. She says, "Excuse me. Can you tell me anything about this rod and reel?"

He says, "Madam, I'm completely blind; but if you'll drop it on the counter, I can tell you everything you need to know about it from the sound it makes."

She doesn't believe him but drops it on the counter anyway.

He says, "That's a six-foot Shakespeare graphite rod with a Zebco 404 reel and 10-lb...Test line. It's a good all around combination, and it's actually on sale this week for $44."

She says, "That's amazing that you can tell all that, just by the sound of it
dropping on the counter. I'll take it!" 

As she opens her purse, her credit card drops on the floor.

"Oh, that sounds like a Visa card," he says. 

As the lady bends down to pick up the card, she accidentally passes wind.  At first she's really embarrassed, but then realises there is no way the blind salesman would tell exactly who had farted.

The man rings up the sale and says, "That'll be $58.50 please."

The woman is totally confused by this and asks, "Didn't you tell me it was on sale for $44. How did you get $58.50?"

"The Duck Caller is $11, and the Fish Bait is $3.50."