NHS-led consortium UnitingCare Partnership was selected from a shortlist of three organisations.
The Cambridgeshire and Peterborough Clinical Commissioning Group (CCG) consultation cost £1m, Stop the NHS Sell-Off claimed.
The CCG said the cost should be seen in the context of the five-year contract.
UnitingCare is a consortium of Cambridgeshire and Peterborough NHS Foundation Trust with Cambridge University Hospitals NHS Foundation Trust.
Martin Booth, from Stop the NHS Sell-Off in Cambridgeshire and Peterborough, said the £1m spent on the process was "both unnecessary and highly wasteful".
However Dr Arnold Fertig, the CCG's clinical lead for older people, said: "The programme costs cover engagement and development work, not just procurement.
"The competitive tendering process has led to the development of new ideas.
"There will be a new-style contract, with payment linked to better patient experience... they should notice that services are better and more joined up."
The campaign group gathered 5,500 signatures from people opposing the transfer of NHS services to a private company.
What does the £800m five-year contract cover?
The CCG currently has seven contracts with different NHS organisations to supply these services.
The other groups bidding for the contract - Care for Life and Virgin Care - have 10 days to challenge the decision to name UnitingCare Partnership as the CCG's "preferred bidder".
The GP-led commissioning group announced plans to outsource its older people's healthcare and adult community services in May 2013.
UnitingCare should begin its new contract on 1 April.
Campaigners have attacked the process to award an £800m contract to supply older people's healthcare in Cambridgeshire as "unnecessary".