Homebrew PCBs

I found this on ebay today:

ebay item #: 360156811112

it may be of interest to the group!

I've been looking around at solder mask, not that I would need it, but it sure would give a nice touch to PCB's I make. 

The seller gives a description of a step by step process with photos. 

If you guys wouldn't mind, may I have your opinions on it? 

To me this product seems like the way for us homebrewers to easily add soldermask to our PCB's. Also, how many square inches would a tube of this size cover? And would it be possible to find this ink elsewhere, and how much might it cost? 


Thanks in advance,
Daniel Bryant