When you first start farming the Grassland will be your best supplier of money. In the Spring, Summer, and Fall you'll find produce on the ground that you can ship. There are 4 spots that they can grow at and once you leave the Grassland to go back to the Island map and then go back, they'll regrow!

Wild Berry (30 G) - Available in the Spring

Cherry (30 G) - Available in the Summer

Mushroom (30 G) - Available in the Fall

You can also chop up the tree stumps here to use for lumber. If you have a level 1 Axe then you'll have to hit the stump six times, with the level 2 Axe three times, and with the level 3 Axe you can smash them up with only one hit. The tree stumps will reappear (just like the berries) when you leave the Grassland and enter again.

During the Winter you can snowboard here. You'll need to buy the snowboard from Lucus' Shop first, then bring it here and equip it. If you do a bad enough job then you'll earn a power berry! Yes, a bad job at snowboarding, not a good one. More information about how to use the snowboard can be located here.