I Wonder Who'd Fall For Something Like This

[ZZ]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8051551078&sspagename=ADME%3AB%3ASS%3AUS%3A1

[john8662]

I'm sure it's a small envelope with some magic beans and instructions on how to plant them...

J

[ZZ]

I thought of something like that or instuctions on not to drive with a heavy foot.

[trbankii]

...instuctions on not to drive with a heavy foot.

That was my first thought for the "won't cost you anything" part of the "secret"...

Let's see. The $3~$5 at a hardware store could be...

Magnets?
Mothballs?
What other snake oil tricks do people say to add to diesel fuel?

[Subzilla]

No, the money covers the cost of a tube of KY Jelly, if you get my drift.