Digital Dissolve is a simple looking trick that blow's the mind of one's audience. It's a little above your budget of $30.00, as it's $34.95, but the effect is well worth it.
The coins that are included, themselves, are worth twice the price of the effect. I bought Silver Dream for $29.95 on E, and the gaffs for it are selling for $34.50. I like Digital Dissolve better than Silver Dream (no offense, Justin Miller) for its price and its unfathomable hard-hitting simplicity. The effect/trick is a methaphorical killer.
You go up to somebody perform the effect and in a couples of seconds (or minutes, depending on their aptitude) you'll flabbergast them over and over and over and over and over again (though performing the effect more than once to the same person/audience would violate the "Canons of Magic" set forth by Penn and Teller).
Cheers,
JTM