need basic EE help

OK, I've been wanting to design this for awhile but due to the fact the cops just showed up after I fired ONE mortar (not to my place, but they're hovering about)...... I NEED to design a very cheap and thus expendable FM receiver that simply closes a relay contact when it gets a matching frequency input of ANY type at X frequency strength..... so simple that it costs less than $5 per unit not including the AAA battery.

I would need what.... a small battery, a Nichrome rocket ignitor to ignite the fuse on whatever it is, a transistor to complete the ignitor circuit when whichever lead gets the signal, a crystal cut to 72.530 mhZ, I would assume a diode somewhere to prevent ambient ignition at the wrong side of the circuit, knowledge on how the fuck to wire it, and I'm sure more stuff I'm missing , hopefully not TOO much. I REALLY would love to have someone help me design this ultra-cheap, expendable, simplest-possible FM receiver that just closes a contact upon receipt of any substantive signal at that frequency. AKA I push either of the sticks on my futaba helicopter radio in any direction, and all low-cost receivers receive the signal and close the circuit, firing the nichrome ignitor and lighting the fuse on whatever it's connected to.


Anyone wanna help ???????? SURELY it's doable for NO MORE than $10 per receiver, PREFERRABLY less than $5 (of course after buying all components in quantites of 100 or more, definetely not expecting that price for a one-off).