http://myfreefarm.co.uk/ Browser game allows you to farm (initially planting crops) and sell your produce to either other players (via a marketplace) or to NPCs, or to complete the NPC quests for extra cash/experience points.
The other big area is the marketplace.
NPCs come to your farm at a rate of 6 in a 24 hour period, starting after you log in for that day. They will buy your stuff directly from you, which helps a little with some of the cashflow issues. You can advertise to increase the number of NPCs. Also NPCs in the market will sometimes have exclamation points over them, indicating that they have 'quests' to do for more points, coins and pDs.
Your second field becomes a chicken coop after the first tutorial level. The chickens in the coop eat the wheat you've grown which helps them to produce eggs faster. Which is a good thing, because an egg takes 4 hours. The maximum wheat you can feed them reduces that to 2 hours. I'm still waiting for my first egg as I'm writing this. The anticipation might kill me. There's a nice feature on the interface for showing how long you have to wait - next to the field is an egg box which is slowly filling up. If you mouse-over the egg box it tells you how many hours and minutes you have until the eggs are available.
Free Farm Game though. Might not work with seasons etc.