There so many web host around. Some are free, some are cheap and some you need to pay premium to be able to avail them.
I have used all of them, from free to premium. I could say that premium hosting are always better than the free ones. Of course it all depends on the size of website you have. For small and starter sites, free hosting is the best way to go.
You can go online with nothing to spend at all. You can get free domain, and free hosting and start posting at no time at all. However, if you want to get serious, buying your own domain name is the best way to start with.
This is now where you want to choose your web host right the first time. List the requirements of your site then research the features of possible web hosts, i.e. if you want streaming video in your site, choose one with FFMPEG feature.
Going to web hosting forums like Webhosting Talk will enable you to read some reviews and recommendation from some users. Server availability and support should be on top of your list. A web site which is frequently offline is not good for business.
Going online starts with a good web host.