You are right, example.blogspot.com doesn't looks professional at all. I will setup a top level domain(www.example.com) on your blogspot website. But to clarify, I won't buy a domain, You'll have to register/buy the domain and I'll setup/redirect that with your blogger website.
Don't know where to buy/register a domain? Try https://www.namecheap.com/?aff=104205 its pretty cheap and reliable
Blog & Magazine
Setup your domain(.com/.net etc) on your blogspot blog.