UK
You will find that in your local area there will be Facebook groups selling all sorts of things to sell including cakes and other things. Just type into your Facebook search engine your area or town and sale or swap and the sites will appear.
But it is competitive and as the other answer has stated you will need a Food Hygiene Certificate (can be done on line) and many people need to know that you are meeting the Environmental Health Standards when you work at home and that may include an inspection as well.
An phone call to Environmental Health without giving an personal details will be very informative,
The you need to have Public Liability Insurance in case you poison anyone!
David,
you can use Blogger or Wordpress for this. Both are free and offer huge possibilities (themes, extensions, plugins, etc).
You also need establish online community on social media sites - Facebook, Twitter, G+, Pinterest, Tumblr and catch social attention. If you look on attached link you can see friend of mine that show his cookies.
lookup wordpress
So ive just 17 and i really enjoy baking and decorating all different kinds of cakes. I was just wondering, what would be a good website or blog site that is free to make where i can show my cakes to people and maybe even advertise. Thank you in advance for answering! :-)