General Knoppix support for those who've read the FAQ at the Wiki
Dell PowerEdge R630 Server 2x E5-2680 V4 = 28 Cores S130 32GB RAM NEW 480GB SSD
$208.99
Dell PowerEdge R630 Server Barebone with Motherboard 2 x Heat Sink 2 x 750W PSU
$149.99
Dell PowerEdge R430 Server 2x E5-2680 V4 = 28 Cores H730 32GB RAM 2x 3TB SAS
$308.99
Dell R630 8 Port SFF 2x E5-2690v4 28-Cores H730P 256GB Server RJ-45 iDRAC ENT
$479.00
Dell PowerEdge R420 Dual Intel Xeon E5-2440 v2 @1.90GHz 32GB RAM No HDD H710
$74.50
Dell PowerEdge R620 Server 2x E5-2660 v2 2.2GHz 20 Cores 256GB RAM 1x 480GB SSD
$139.99
Dell PowerEdge R620 Server - 256GB RAM, 2x8cCPU, 120Gb SSD/3x900Gb SAS, Proxmox
$320.00
1U Supermicro Server 10 Bay 2x Intel Xeon 3.3Ghz 8C 128GB RAM 480GB SSD 2x 10GBE
$273.00
Dell Poweredge R720 8-Bay 2U Server 2* Intel Xeon E5-2690 2.90Ghz 96GB No HDD
$239.99
DELL PowerEdge R430 8SFF 2x E5-2687Wv3 3.1GHz =20 Cores 128GB H730 4xRJ45
$364.00