It just cracks me up that whenever this comes up, nobody looks at the REALITY of audio production!
Reality 1 - Probably not so great of a tune. Maybe not so bad, but 80% of the stuff I hear here just is not very skillful songwriting/arrangements! I don't care how much you polish that turd of a song with high dollar mics and preamps, if it ain't arranged right, your mix will suck!
Reality 2 - When the most asked question is "What is the cheapest "good" *insert audio component here* I can get" at this site, you HAVE to expect that:
a - The person is very inexperienced
b - Has built a WHOLE STUDIO on a budget that is probably less than one beautiful AKG C-12!
On top of all of that, this person is going to probably play an Ibanez $300 special guitar through a POS Marshall Valvestate or Line6 crap thingy. The drums will have 2 year old heads, and a drummer that doesn't understand CONSISTENCY. The bass player will give you a blank stare if you ask if he has EVER set the intonation on his bass!
With all that marginal talent, this inexperienced engineer, who is probably the lame guitar player in the band, is going to wear two hats that he is FAR from being ready to wear, Producer and Engineer. Of course, the singer who couldn't carry a tune if he owned an ipod is going to have some "opinions" about the production that just HAVE to happen! If he don't get his way, he will of course refuse to sing.

(although, wouldn't that usually be doing us a big ass favor?

)
So that chinese mic to that dmp-1000PRO pre, to that $100 mudaudio soundcard, and butchered in Adobe Audition at "32 bits!". This is gonna be mixed in lame guitar players bedroom of course, usually using self powered monitors that only make marginal playback speakers for mp3's.
He is not going to use ANY reference material as he goes along.
He is probably not even going to reference song to song on this production!
So after ALL of that, you guys think that he should cough up like $500 to have a "pro" master it?
I tell you what, grab the best "free" limiter you can, and whip out the best eq you can get your hands on. Run that audio through the eq first, then the limiter. Try to achieve about a -13db RMS level and call it good. Try to make all the songs sound about the same in the eq department. Make all the songs about the same perceived level.
Fade them in, and fade them out as needed. Apply some 16 bit dither and save as 16 bit. Make an order for the songs and burn a freakin' disk. Go listen to it in your car, your home, on your friends Dell desktop with "Bose" surround speakers, and anywhere else you can think of. Listen for some "problems" in the eq and if need be, go back and "fix" them.
Burn your final master and start duplicating them and sell/give them away as quickly as possible.
Trust me, don't go wasting your money on a overpriced mastering engineer until you are SURE you can sell AT LEAST 3000 copies of your release! It simply is not worth it otherwise. Spend that money on some "promotion" to sell some more CD's.
If people like your music, they will like it whether you "master" it, or if some schuck with Wavelab and Waves Mastering Bundle, or Mr.Gear God Complex does it. It won't matter ONE BIT to your VERY SMALL LOCAL AUDIENCE WHO THE FUCK MASTERED YOUR CD!!! In a week, the buzz is usually gone, and the drummer is showing up late to every practice, the singer is looking for a new girlfriend to live with, and tips are down at your Pizza Hut delivery job! No need to worry about getting "the very best" out of your demo that was doomed when you first decided to do it yourself!
Your other route to the above is to go the FULL PRO route! If you fucking care ONE IOTA about your audio, you won't attempt to produce it yourself UNLESS you have a LOT of experience doing other people's music! You will pay for a "pro" to record/mix/master is! It ain't gonna be cheap going this route! Plan on spending at least $500 PER SONG for recording/mixing, and consider upping that to around $1500 per song if you really wanna rock! Then, you can really take advantage of Mr.Gear God Complex "mastering engineer" to the fullest! He will have SOMETHING WORTHWHILE to work with, and you can expect your finished product to SOMEWHAT compete with what you hear on the radio.
So, what I am saying is, if you are going to recommend a "mastering engineer", you better recommend they use a tracking and mixing engineer too! Otherwise, it is just silly talk!
Mastering is NOT rocket science by any means! Simply, they use some eq, some compression, some limiting, sometimes some expansion, stereo enhancing, etc...to "pretty up" the audio a bit. Seldom do they do very much! If they have to do more than around 2 or 3 db of eq, and more than around 4dB of gain reduction on the compressor, and maybe around 4-6db of gain reduction on the limiter, then the mix is fucked! The mix is probably fucked because the tracking was fucked! The tracking was fucked probably because the performance and source sounds were fucked!
It starts at the beginning folks. The VERY beginning. Most guys would be spending better money by buying new drums heads and tuning them, and intonating the guitars, and probably renting some QUALITY amps and mics more than some gear snob trying to polish the turd at the end!