hi , about mixing and mastering ..
I have solution ..
Lot of practice , try to tweaking any gear or digital software u have , your EAR " most importtant " ..
Cheers
Acctually, mastering is a process itself. And its art too. Just like mixing.
And I think that 1000~1800 bucks for a professional master is a no brainer. Thats Bob Katz price.
You won't get a "master" just throwing a plugin, you have to make the CD ready for reproduction too.
Although, if you want that 'mastered' feel for that ultra small budget production, go for Ozone.
But if you just want loudness, just any limiter that comes with your DAW will do the job. The next step would be Slate FG-X, but I prefer Ozone.
More important than those plugins would be a treated room and propper monitoring system.