There's free blogging softwares to help you get started. Easy enough, just remember blogs are usually written in first person, not overly long or boring.
If you have a google account they're have a good blog creator
tumblr! its a really good site! its free and you can get popular easily. also, their are plenty of other humor blogs for inspiration :)
I would LOVE to start a humor blog. Are there any good/ trustworthy website that can help you create one for free?