Taking the meaning of blood money to a much more civilised and literal level you can receive cash as compensation for donating blood.
In the UK you can donate blood to the NHS for free which is vital for use in life saving operations. You can also get paid to donate blood for medical research. Some of the companies that offer this are listed below.
With each blood donation there is a checklist of requirements which you need to meet to be eligible to participate. This involves being of a certain age, height, not having taken any drugs etc. Each company will have a slightly different list of requirements.
Sites to use
NHS Blood Donation – Donate blood to the NHS and help save lives.
Research Donors – Get paid to donate blood for medical research.
Trials 4 Us – Get paid to donate blood for medical research.