You need to get $200 in order to buy a pig. Do not buy anything else. When the grizzly bears and pandas appear, catch one of each. Send one to the market for $180. When the storage is empty, put the other bear in. When the cart returns, send that bear to the market for $120. You should now have $1,100 which should be used to buy a pig. Note: There will be an attack immediately after the cart returns on its second trip.