Answer:
You know the code obviously, right?
If you have no codes, look them up online,
there should be tons. So, once you have
one written down, talk to Tom Nook
at his market. Tell him "other things"
and then "say code". Enter the code EXACTLY
as you see it written. A slight mistake won't
get you anything. So, here is a free code to try:
WB28pARAcnownU
jMCK%hTk8JHyrT
sorry if it does not work. try it out to see what you get!