If you do want to use the 10Watt bulbs, you will need co2, in my humble opinon - however, you can probably find a 3 watt curly cue screw in flourescent at your local hardware store. Moss doesn't need a lot of light, if that's the only plant you want. Especially with light coming in the window - you won't want more than 3 watts. Is there a reason you would like to avoid filtration? You can get away with a small sponge filter, like was posted above, but you can use just an airstone as well, as long as you keep up with water changes, and make sure the tank is cycled first -- IF all you have are shrimp in that tank. A larger bioload, and that won't cut it. I'd buy the best heater you can - some of the cheaper ones are prone to malfunctioning!
Oh, and I've found shrimp (depending on what kind you get) prefer around 76 degrees.
Snails are my friends