So you want to pound some metal in your own backyard/workshop/garage. You're going to need a forge to get the job done, unless you want to be one of those people that just uses torches. Sure, they have their uses and you may need them unless you have a full-scale blacksmith shop at your disposal, nontheless it is best to get a forge and do it right. But, slow down, don't just go out there and get any old forge. There are a few things to consider first.
First amongst those is price. Blacksmiths tend to be cheap... I mean frugal and prudent with their purchases. If you are just getting started, don't go out there and buy the finest coal or gas forge you can find. Sure, they have a high resale value and you are almost guaranteed to find a buyer, but you are going to need that money for supplies. Start small, if you like it, progress to a larger/better forge if you feel the need. Price, though, is tricky. Assuming you have access to a good number of power tools, you can put together a coal or charcoal forge from old iron car parts for about $50-$75. Any junk yard will have everything you need and there are plenty of tutorials online about how to set one up,
What if you don't have the tools and can't get them? Then, my friend, price goes up. There are a number of prefabricated forges out there, but before you drop money on those you need to consider what fuel you want to use. Which brings us consideration two...
What fue do I choose? Your options are basically coal, charcoal, or gas. They all have their merits and they all have different price points. Gas is easy to get, burns at a constant temperature (essentially. And you can adjust it too - no more scorched metal!) , and easy to light. Depending on how you manage your fire or the work you are doing, though, you will use a lot of gas. They can get expensive for something that may just start out as a hobby ($600+ for a decent low-range forge). The way I look at it, you will learn a lot from trial and error. That said, solid fuel forges (coal and charcoal) make you pay more attention, require effort to keep at a good temperature, and have a higher learning curve, but are much more rewarding, in my opinion. Cheaper too... I mean more financially prudent for the beginner smith.
Solid fuel forges have their own consideration, though, outside of just learning to use one properly. You will need to check with your local laws on burning coal (almost every county could care less about someone burning charcoal). If you plan on making a business out of your endeavors, you may even need to register with the EPA, despite the fact that you would be seriously hard pressed to burn enough fuel for them to care. Essentially, if you burn coal and make money off of it they want to see how you do business. At worst, you get an EPA rep to check out your forge and that is about it. Keep in mind, not all counties/states require this, but it is something to look into if you consider coal. No one wants the Man knocking on their door when they were just trying to have some fun.
Which is why, finally, I recommend a charcoal forge for someone that wants to see if he or she wants to invest more time/money into this. Cheap to buy or make (really, an old grill and a hair dryer will hold for quite a while before you need to worry about getting serious), fuel is extremely easy to acquire but does not last as long as coal, and as far as the government is concerned, you are just burning something in a grill or fire pit. Since it is a controlled fire just about every local law is okay with it (still check, chances are you live in the one area you can't, because that's just how lucky you are), you are burning a wood product and not a fossil fuel, if something goes terribly wrong you don't need to worry about any explosions, and if you run out of charcoal just use scrap wood. Yes, it will take longer to heat up the metal, but as far as learning what to do you are likely better off for it. If you want a reliable charcoal/scrap wood forge that is actually sold at a reasonable price, check out Whitlox Forges (www.whitloxhomestead.com).
You have some options to consider and some thinking to do. Look at local laws, check that bank account, consider how much patience you have and how devoted you think you will be. Give it a shot, you may find your calling, a hobby, or painfully learn that playing with hot metal is not for you. Hey, at least you tried.