Gold- and silver-quality crops sell for more than the base sell price, so you should definitely sell them early on before you can craft them into anything better. This will likely be your main source of income in the first year of the game. However, you should absolutely hang on to base-quality crops.
Bat Wings are monster loot that is acquired by killing bats in the mine. They are used in crafting Lightning Rod. All villagers hate receiving them as gifts.