I never like this question.
I am not a fan of just designing a logo as an adornment. A logo is almost the end point of the discussion, not the beginning.
A logo is the result of a conversation, an understanding by the designer of the client’s needs. Who they are. What they do, Who they want to appeal to. How they see themselves. It is then a designers job, through knowledge and experience to be able to visually communicate this ethos and ideals. A logo on its own is as pointless as a car tyre without a car. It is almost pointless – unless you just want something to push around all day. The logo should be part of a unified identity that does an actual job. A visual mnemonic that you can attach all the relevant emotional and semantic associations to. If it is not, clients are just pissing their money away on pretty (and sometimes, not so…) adornment, rather than visual communication that will actually work for them.
I know this all sounds hi-falutin’ (and perhaps more than a little pompous) but brand identity is not just something reserved solely for large corporates. It is just as important, if not more so, for the local butcher. They have to communicate their ethos effectively, otherwise people just go to Tesco (et al) because they can get battery-reared meat cheaper. Personally, I get more pleasure and satisfaction working for smaller companies or organisations that I do with larger corporates, when working on branding projects.
To that end to price a logo without knowing the scale and extent of the job required is pretty difficult. For example, I use the same approach whether it is for a local shop, or a multi-national. Find out what they want to say and then help them say it to the right people. Simples. (See what I did there!). This means the cost for a brand identity project can be anything from £400 upwards to, well, if you are lucky enough (and experienced enough) to get a bite at the larger clients, it could run into years of work and thousands of pounds.
Hope this helps.