I recommend something other than
a Raspberry Pi 3 for a multiple node set-up. I have
several instances of single and dual node installations
using usbradio on INTEL ATOM processor based computers, as
follows.
Intel D2500 fanless motherboard - about $60
A Mini-itx Case/Power Supply - about $50
2 gig of RAM - about $16
Samsung 16 gig SSD MMBRE16G5MSP - about $20 (used)
This makes a very capable fanless computer for about
$150.00. Yes - it's not $40.00, but it also doesn't have
the machine gun effect of running usbradio on a Pi3. I've
had zero issues using these used-reclaimed SSD drives. eBay
is a good source for everything.
Kevin W3KKC