I've had around 15 sittings. Mainly a sitting has equalled a finished tattoo (I tend to have had a lot of smaller things rather than gone for a sleeve, but i'm toying with the idea of "connecting the dots" and just making sleeves of them if I find an idea I like enough), and an average sitting for me is around 2 to 3 hours. For that, it's normally around a couple of hundred quid, depending on colours, detailing etc.
I have had a couple of small tats done, which cost as little as