root/npc/sample/npc_dynamic_shop.txt @ 1

-       shop    dyn_shop1       -1,501:50

prontera,181,200,4      script  Dynamic Shop    123,{
callshop "dyn_shop1",0;
npcshopattach "dyn_shop1";
end;

OnSellItem:
for(set @i, 0; @i < getarraysize(@sold_nameid); set @i, @i + 1){
        if(countitem(@sold_nameid[@i]) < @sold_quantity[@i] && @sold_quantity[@i] <= 0){
                mes "omgh4x!";
                close;
        }
        if(@sold_nameid[@i] == 501){
                set $@rpotsleft, $@rpotsleft + @sold_quantity[@i];
                set Zeny, Zeny + @sold_quantity[@i]*20;
                delitem 501, @sold_quantity[@i];
        } else {
                if(@sold_nameid[@i] == 502){
                        set $@opotsleft, $@opotsleft + @sold_quantity[@i];
                        set Zeny, Zeny + @sold_quantity[@i]*100;
                        delitem 502, @sold_quantity[@i];
                } else {
                        mes "Sorry, I don't need your items.";
                }
        }
}
deletearray @sold_quantity, getarraysize(@sold_quantity);
deletearray @sold_nameid, getarraysize(@sold_nameid);
mes "Deal completed.";
close;

OnBuyItem:
for(set @i, 0; @i < getarraysize(@bought_nameid); set @i, @i + 1){
        if(@bought_quantity[@i] <= 0){
                mes "omgh4x!";
                end;
        }
        if(@bought_nameid[@i] == 501){
                if(@bought_quantity[@i] > $@rpotsleft){
                        if($@rpotsleft > 0){
                                set @bought_quantity[@i], $@rpotsleft;
                        } else {
                                mes "We are out of red potions!";
                                close;
                        }
                }
                if(Zeny >= 40*@bought_quantity[@i]){
                        set Zeny, Zeny - 40*@bought_quantity[@i];
                        getitem 501, @bought_quantity[@i];
                        set $@rpotsleft, $@rpotsleft - @bought_quantity[@i];
                } else {
                        mes "You have insufficient cash.";
                        close;
                }
        } else {
                if(@bought_quantity[@i] > $@opotsleft){
                        if($@opotsleft > 0){
                                set @bought_quantity[@i], $@opotsleft;
                        } else {
                                mes "We are out of orange potions!";
                                close;
                        }
                }
                if(Zeny >= 200*@bought_quantity[@i]){
                        set Zeny, Zeny - 200*@bought_quantity[@i];
                        getitem 502, @bought_quantity[@i];
                        set $@opotsleft, $@opotsleft - @bought_quantity[@i];
                } else {
                        mes "You have insufficient cash.";
                        close;
                }
        }
}
deletearray @bought_quantity, getarraysize(@bought_quantity);
deletearray @bought_nameid, getarraysize(@bought_nameid);
mes "Trade done.";
close;

OnInit:
npcshopitem "dyn_shop1", 501,40,502,200;
set $@rpotsleft, 10;
set $@opotsleft, 10;
end;
}