Once you reach the second day, you'll receive a letter. You can travel south from Pelican Town after that, and you'll meet up with Willy the Fisherman. He gives you a fishing pole, which allows you to fish and potentially earn income of more than 300 gold per day (plus more besides, if you eat food and replenish your energy so you can keep at it). Early in the game, that extra income will allow you to invest in faster means of earning money.