Learning to do pro level mastering is not an easy thing to do and escaping you own bias is also not easy. Just why the idea of another set of ears comes into play. Many pro studio engineers do not master their own stuff.
Five bucks? Less than a cup of coffee at Starbucks. Having said that most of my hobbies have become more expensive than I can any longer afford. Two days of fishing in my stupid little boat now cost around $1500. I just hope I die before I run out of money...lol
Billy
Even with iZotope Ozone mastering is a steep up hill learning, and the tool, though brilliant, is not for free - so I second your world class sentence
"Most of my hobbies have become more expensive" - that's indeed 9999% true
I'm not poor - I just have an expensive hobby