What you are buying
A logo on its own is a mark. An identity is the mark plus the rules: which version to use where, what the colours are in print and on screen, which typefaces pair with it, and how it behaves at small sizes.
A vectorisation job — turning an existing logo into clean, scalable files — is a different service again, and priced accordingly. Knowing which of the three you need is most of the conversation.
What moves the number
Three things drive cost: how many concepts you want to see, how many applications the mark has to survive, and how much research sits behind it. A mark that only ever appears on a website is a smaller job than one that also has to work embroidered on a uniform and printed on a vehicle.
The number of revision rounds matters too. Open-ended feedback is the most expensive thing in any design project, which is why we agree the rounds up front.
What to ask for in the handover
Always ask for vector source files, not just PNGs. You want the logo in horizontal, stacked and icon-only versions, in full colour, single colour and reversed out for dark backgrounds.
Add profile-ready crops for the platforms you actually use. It costs almost nothing at the end of a project and saves a designer fee every time you open a new channel.