I charge $150 per song and accept credit card payment or PayPal.
1) Send me your MP3 or WAV stereo mixes or stem mixes of each song. I accept 50% payment upon receiving your files.
2) I'll play your songs and send you back mp3 stereo roughs to see if you like my approach. If you don't like my first pass, I'll play again.
3) Once you approve, I accept 50% payment and send you your WAV files.
Sometimes I'll charge a little more, depending on the nature of the work involved.
Contact me at email@example.com