function Go {
set lastwarp$, getarg(0);
set lastwarpx, getarg(1,0);
set lastwarpy, getarg(2,0);
warp getarg(0),getarg(1,0),getarg(2,0);
end;
}
change to
function Go {
if (select("Pay 20k Zeny", "Cancel") == 2) close3;
if (Zeny < 20000) {
mes "You don't have enough Zeny.";
close3;
}
Zeny -= 20000;
close2;
set lastwarp$, getarg(0);
set lastwarpx, getarg(1,0);
set lastwarpy, getarg(2,0);
warp getarg(0),getarg(1,0),getarg(2,0);
end;
}