Every such association may collect, at the time of the issuing of a policy, a membership fee not exceeding five dollars, and, if insuring property, a percentage of the amount insured not exceeding two and one-half percent, as an advance assessment, as the bylaws may provide. From the amount so collected, a contingency fund may be created, and such fund may be maintained and added to from any other funds collected by the company in the manner provided in the bylaws.