Hello there,
There are a lot of different subjects in this post. You should try to keep your questions as simple and small as possible and only one subject/question at a time is also a good idea, for future reference.
This will depend on whether or not you want to hack wordpress's website or sites using the wordpress system, I assume the last one. I don't know about eblogger, but wordpress is a pretty secure system indeed. Finding vulnerabilities in wordpress is going to be a tedious and complex job, but nothing is impossible. Zero day exploits are found every day, even in the biggest and most "secure" systems out there. I would suggest learning PHP and web application security problems in depth before having a crack at wordpress tho.
When it comes to VPN's and proxies, I would never ever buy one ready to use. Make one/set one up on your own, that way you are in complete control over what gets logged and who can use it. But yes, of course you have to get a server of some sort first. Or just any machine that you have control over.