You might also want to consider using Adsense (although I'm not sure that you could use it on a Yahoo blog - but you can use it on a Blogger blog)

All the ideas that you mentioned sound like very viable business ventures. You also mention selling stuff and hopefully you know about Ebay. Lots of people have started their own business selling things on Ebay. They expand on it by going out to flea markets and stuff and finding other things to sell on Ebay and others increase their business more by having gained a reputation where buyers seek them out specifically when they are looking for certain items to buy.

There are a lot of legitimate articles online about different ways to earn money with your blog (or website)