Nope. You have to buy .com domains and then hosting (or get free hosting with lots of ads, you have to fiddle with DNS servers though). Most of us aren't in it for the money, but that doesn't mean it's free.
You could always use a free service like wordpress. It won't make a great website but it's been adequate for my needs which are to post updates occasionally, post pictures of my geckos and have some place to direct people so I don't have to endlessly email caresheets and pictures to individuals.
MB/space is "megabytes," and refers to how much storage you'll be allotted.
Like the rest of us, we're not really doing this to make a profit, it's a passion for sure; and one that isn't always cost efficient.
When it comes to a website, you should see about hiring someone to do it for you if you're not knowledgeable at all. I'm an RGD (Registered Graphic Designer) and a Web Designer/Developer; and I see time and time again a website that is poorly constructed/full of errors; and always suggest someone to at least talk to a professional.
You can get a web address for free from many places and even a basic layout for free. If you do want to put a little money into it you can get some domains as cheap as $60 for at least two years. I know it seems like a big investment but it is worth it if people check it out. I do suggest talking to a professional for help because coding a website is quite difficult. The problem with professionals are that they are expensive. Here is a web place I used for one of my websites. http://www.webs.com/