Riamus2, \54 is an octal character and is equivalent to \x2C and mIRC's $chr(44)
And \44 is the same as \x24 and $chr(36)
It's force of habit I use the octal chars. You can do it as \$ for it to be escaped with a backward slash \ , since the dollar sign in regex has its special meaning. For the comma, though, it's not necessary to make it literal. I hope this clears up your confusion.
P.S. you should be able to find a list of octal characters by googling one.
