I couldn't find anything regarding actual physical dealer locations, or a store locator of some sort. If you have access to an AirVoice Wireless phone, there may be a store locator application on there. If not, it looks like your best bet is to buy their AirVoice Activation Kit directly from their website. I've seen some references online to people having purchased an AirVoice GSM SIM card on eBay, however, I'm not sure that I'd be comfortable recommending that.
You can also find an AirVoice Wireless activation kit here at MrSIMCard.com.
On their website, they also indicate that the take payments at Western Union, however, they don't indicate whether or not activation kits (i.e. SIM cards) are available there as well; I doubt it, as Western Union is largely a payment processor, and it's highly unlikely that they carry physical inventory (i.e. SIM cards).
Lastly, you can try calling AirVoice at 888-944-2355 to inquire about whether or not there's a physical location that you can go to in Daytona Beach to purchase a SIM card.
