I recently purchased a new domain for a project that never went ahead, and I've decided I'd like to use it to build a blog site, which I plan to build up and eventually sell. I was planning on building the site with WordPress and hosting it on my shared hosting but I've never sold a site before so I was wondering how it works when it comes to selling it? Is it acceptable to transfer the domain and all files for the site without any hosting included?
Why not? It's really up to you and the buyer to negotiate what they want. Any experienced web person will probably have their preferred hosting service and will want to move the hosting to their own servers. If they want your blog content, then you should at least export the DB and any resource files so they can replicate the site when they move. If they only want the domain name, then your content may be unimportant to them.