CR25ing / CR25Wing on UK ebay, prices start at 30£.
Will happily route 1gibt, add separate wifi, of your choice, unless you get the W model.
There are two USB (2.0) ports, you can also install a 2.5" SATA drive inside.
It's a x86 device, you write the openwrt image to the SSD/HDD, or the CF card.