Ka-ching!

I’m visiting area schools today, so there’s just time to define two words appearing in today’s Frank & Earnest comic strip.

Ka-ching - an imitation of the sound made by a cash register, according to
http://www.urbandictionary.com

Mantra - taken from Hinduism, it is a “hymn or portion of text … chanted or intoned as an incantation or prayer,“ according to Webster’s

By the way, "ka-ching" is an example of onomatopoeia.  That is when a word imitates a sound.  Other examples include buzz and tinkle.