I have a project  where I will need a decent number (100+) of Openwrt boxes that will run in various locations linked to a bespoke sensor board that has a serial connection. I'm thus looking for the cheapest device that runs Openwrt and has a 'real' serial header - ie one with pins. For this project I dont mind cracking open plastic cases, but I cant risk soldering onto little pads or direct onto chips.

Candidates so far - TP-Link 3020
Ubiquiti Airrouter

Both have headers on pins, and cost £20 / $30 including sales tax in UK.

Any others I might have missed? Some of the TP-Link stuff is cheaper (and comes in a more hackable case) , but doesnt have pin headers. I dont actually need wirless either.

Thanks in advance.