I currently have 3 servers with a full 45u server rack in my room. All of the servers I bought off ebay for $150 each or less including all things needed to run like hard drives, ram and cpus. I currently have one Dell Poweredge 750 (dual core, 2 gigs of ram, 1x 86gb SAS Hard drive) running pfsense as a secondary router for 5 ips I own. I also have one Dell Poweredge R310 (Quad Core Xeon 2.4Ghz, 8gb ram, and 2x 300gb SAS Hard drives) running plex and zpanel. And finally I have a beast Dell Poweredge 1950 with two Xeon Quad cores with a total of 8 cores running at 2.5Ghz, with 32Gb of ram, and 2x 360gb SAS Hard drives. I mainly use this server for VMware and Zpanel. I also host a game server and a database for that game server on Zpanel. All of these amazing pieces of art are wrapped in a Cooper-b Line 45u server rack. Now is this overkill, YES, COMPLETELY OVERKILL for what I am using them for. But do they get the job done for a cheap price? Yes. Here are a list of prices for all of the items in the rack.
Dell Poweredge 750 - $65 + $12 shipping
Dell Poweredge R310 - $135 + $free shipping
Dell Poweredge 1950 - $80 + $32 shipping
Dell-PowerConnect 3348 - $40 + $10 shipping
Cooper-b Line server rack - $50 + free pick up
A box of cat6 ethernet cabling kit - $50 + $20 shipping
Total = $495
A server like the one you listed above surely capable of running a moderately sized minecraft server. I honestly say "go with whatever your heart desires". But be carefull and don't buy anything overpriced or something that looks a little "off" on ebay. If the person doesn't list any specs or details I usually skip over them and their dream like prices.