it just doesnt work that way..

your options are a switch across the coin switch, an extra leaf on the start button to add a credit each time, an alltek board, setting replay to 10k so you always get it, setting a coin slot to 15 credits per coin and using it as a money box.. or . i probably missed one . you get the idea. there is no 'free play' setting on the standard mpu.

cant type ...blinded by shiny door

you want single pole single throw SPST push on momentary N/O ( normally open).

jaycar CAT.NO: SP0700 is an example but there will be other smaller ones