Hmm those deals with jumba are terrible, try ioflood.com which is located in Texas right next to the international pipeline ping is sub 200ms worldwide.
Or if you want an even cheaper vps provider try
http://alienvps.com/vps-hosting/ you can get 2gb ram from them for only $20 a month, thats enough for about 30 players.
If you need help setting up a minecraft server on a centos install just read my tutorial
Regards
