Lithium batteries are expensive and you deserve to get a long battery storage life from every penny that you spend on both the batteries and the BMS.
There are three types of lead acid marine batteries. These include the flooded batteries (including sealed), gel batteries and Absorbed Glass Mats (AGMs) batteries. These are rated depending on the energy output measured in ampere hours. The output, together with the lifespan, is what typically dictates the price of the batteries.