With 10 million members, each person pays much less every year. If we assume that only a small number (0.5%) of members will need a funeral, and each funeral costs £20,000, then the total money needed for all funerals in a year stays the same. But because there are so many members, the cost is spread out more:

Total money needed for funerals every year = 5,000 funerals x 20,000 per funeral = 100 million

What each of the 10 million members needs to pay = 100 million total cost divided by 10 million members = £10 per member

So, every member would only need to put in £10 each year, which is ten times less than what they would pay if there were only 1 million members.

The Vision of 100 Million

If we grow our group to 100 million members, everyone saves even more:

What each of the 100 million members needs to pay = 100 million total cost divided by 100 million members = £1 per member

With this many members, the yearly cost for each person is just £1, which is as cheap as buying the least expensive salt.