Are you looking for information on the cost effectiveness of different treatments, or cost-benefit analyses? Published economic evaluations are a good place to start, but they're not always easy to find in the literature, so below are some suggestions for places to look and ways to search for them.
Once you've found an economic evaluation, you could use the CASP Economic Evaluation Checklist to critically appraise it.
CEA Registry
The CEA (Cost Effectiveness Analysis) Registry is a collection of over 5,500 articles containing cost-utility analyses.
NHS Economic Evaluation Database (NHS EED)
The NHS Economic Evaluation Database (EED) contains details of articles containing economic evaluations of healthcare interventions. It covers the period up to the end of 2014 (sadly, it is no longer being updated with new information)
It can be searched via the Cochrane Library, and results are shown in the 'Economic Evaluations' section of the results list.
Medline
Medline is a very comprehensive database, with coverage of all areas of medicine, including nursing, allied health, public health and mental health.
Economic evaluations can be found by using a search strategy such as this one for Medline:
(ec).fs OR (cost).ti OR exp *"HEALTH CARE COSTS"/ OR exp *"COSTS AND COST ANALYSIS"/
Copy and paste this into the search box and run the search, then carry out your subject search and combine the two. More strategies can be found on the McMaster University website but they will need to be adapted for the NHS databases.
EMBASE
Excepta Medica (EMBASE) covers all aspects of medicine, nursing, allied health, health policy, and public health. It is particularly strong on pharmaceutical information, and has an emphasis on European literature.
Economic evaluations can be found by using a search strategy such as this one for EMBASE:
exp *"COST EFFECTIVENESS ANALYSIS"/ OR exp *"ECONOMIC EVALUATION"/ OR (cost).ti OR (economic).ti,ab
Copy and paste this into the search box and run the search, then carry out your subject search and combine the two. More strategies can be found on the McMaster University website but they will need to be adapted for the NHS databases.