A resource cheap way, if you don't care about looks, is using water as a "shield" around your house. Pour it so it covers most of your house, except the door, and have it run down into a second moat. Have a border of dirt between your lava and water moat so the water doesn't put the lava out. This will not look top of the line, but will help out if your resources are limited. Iron is easy to come by, and water is too. This will also shield against creepers blowing your house up, if they ever manage to get close enough. And if you happen to fall into the lava moat by accident, you have water right there to put you out.