you can do the digging minigame for free if you fly in the the place you dig for stuffbut you still only can dig 10 things. btw what happens if one digs up mmore then 10 items?
I was bored and i wanted to test it. Its something along the lines of this.
one dig over, warning
two digs over, 10 rupees
three digs over, 100 rupees
four digs over, 500 rupees
5 digs, all rupees gone.
But again, these are what i remember, just make sure you only dig 11 at max!