plugging bride friendly society into search engine on Manxnotebook will find a bit of info:

Basically these societies offered some protection against sickness (and would pay some money to any widow) but not against unemployment. Often some entry fee plus around 1s a week would be required as dues.

A major problem of the early societies was their lack of understanding of sound actuarial practice - when a society was formed, generally by young men of similar ages, a flat weekly rate independent of age, seemed to provide capital growth (so much so that some societies would fund an annual dinner). But as members aged their demands on the fund increased - prospective young members saw that it would be in their better interest to found a new society thus avoiding the need to support 'drones' (as so called by one such Ramsey breakaway group). National friendly societies, such as the Oddfellows and Rechabites, had been forced to put their finances on a sound actuarial basis in the mid 1850's and after some loss of membership prospered from then on.

The capital was usually 'banked' in terms of giving mortgages on property - the interest of which + the weekly contributions funded the sick box.
The Bride soc was founded in 1833 - I suspect it folded c.1914 when National Insurance was introduced.

If you want help with will let me know.