This is the easiest and cheapest way to get a tree plant in your home, at least that's been my experience. The first step is to buy a nice ripe avocado at your local store and make some delicious food with it. Keep the pit and wash it off.
Get a pot and soil to plant the pit. Yes, plant the pit in the soil because this is the easiest method. I have tried that hanging the pit with toothpick partially in a glass of water and that has never worked for me. Putting the pit in the soil has worked every time. I helped a friend grow one, who had tried to start it off in the glass
of water and it failed. I had him do this method and he now has a tree
of about 5 feet tall and it took about 3 years to reach that height.
To plant the pit, put the large round end in the soil and push the pit about half way down leaving the top pointy half sticking up out of the soil.
The tree will go through phases of growing tall, growing leaves, growing branches, thickening up, so don't grow disheartened if your tree seems to have stopped. It is probably getting thicker or starting a new phase.
By the way, this is a great project for kids to do, but they will need patience for a few weeks before seeing results. If you have always wanted a tree plant in your home, here's your chance to grow one from scratch. You will the love the results.