Carina Andersson and Rickard Franzén at the Swedish National Heritage Board have put together a report in Swedish titled “What Does Contract Archaeology Really Cost?”. Their answer to the question is, briefly, “less overall than the County Archaeologists would actually allow”. County Archaeologists all over Sweden put out lots of contract work to tender and select who will do each job at what budget. And the archaeologists on average keep well within these budgets. Very likely, this is helped to a great extent by sites that look promising but turn out to be duds.
Another way of answering the question is that in 1996-2006, Swedish contract archaeology cost from 150 to 330 million kronor per annum, which currently translates to $19-42 million or €15-33 million. Divided by Sweden’s population the money translates to about $2-5 per capita, though not all of the money is of course public funds.