My understanding is that a fireplace insert is something that you install into the firebox of an existing fireplace. If you do not have a fireplace, an insert is not the thing for you.

If you are considering building a fireplace, you need to know that the conventional ones are not energy efficient and can actually send heated air up the chimney, although they are pretty. The optimal technology is something called direct vent which is typically available in either natural gas or propane gas. With such a system, the firebox is entirely sealed and there are 2 vents to the outside -- one to exhaust the fumes and the other to bring in air to feed the combustion. These units take a few minutes to heat up, and then they're like a blast furnace, really serious heat. Depending on the particular brand, you can get a very pretty realistic looking flame.

But if you're wedded to the fun of burning wood, direct vent is probably not for you.

To answer your question about a fan: They do work to help distribute the heated air, but some of them can be pretty noisy. You have to pick and choose.

Look in the website hearth.com. They have a chat room where you might get some more advice.

Consider a Rumford fireplace, that is the most efficient form of open fireplace. But I doubt you could get one for $3,000 or less.