there's many ways to get BTC.
- faucet
- trade
- mining
- campaign
- ads on blog/website
- do some task
- gambling (i dont suggest this one, too many risk if dont have godly luck

)
Getting ads on websites or blogs is not an easy task at all, as far as i know a website or a blog has to spend almost 6 months to get accepted by advertisers to get ads, and it is not an easy task to start a blog and run it for 6 months to get ads then, if someone has a lot of free time he can surely do that otherwise it is really time consuming.