pita = stopping dead

'Mini youkai 500 yen a time' = M.J.: Either a double entendre, or a
pun. I'd assume the former except for that little question mark. Virtually every object in Japanese has a separate counter--flat things are one 'mai', cylindrical things are one 'hon', cars are one 'dai' etc. Sort of like the specialized aggregate words for animals in English: an exaltation of larks, etc. There's no special counter for youkai--you can use the human counter 'nin' or the animal counter 'hiki'--but if there were it might be the 'kai' of youkai. 'One youkai' would be 'ikkai'. However, this sounds like the ikkai of 'one time' and so the artist has drawn it with that kanji.