Price depends on space available and sponsored ads appearing or not.

It doesn't. I'm not sure about getting an ad free site without space but in terms of space which is just one factor, while an individual company will often have lower and higher end packages, prices vary trememdously.

Other factors to consider are bandwidth and depending on what you want to do, other facilities such as email, scripting, a database, etc.

The most generous allownaces of the sites I have looked at for this thread is the lypha site I linked to. They are not the most expensive, wanting $7.95pm (or $6.95 for 2 year contract) for 50Gigabytes storage space and 1000Gigabytes monthly (33GB daily) bandwidth together with tools, that enable dynamic websites, free scrips such as a fourum, etc. One could host a large and busy site with that sort of spec.