The larger the battery, the larger the price tag. That's because larger batteries provide more power. A battery with a long lifespan will cost more than one with a shorter lifespan. The reserve capacity (RC) number lets you know how much stored power the battery has, so the higher the RC number, the higher the cost. The same holds true for the number of cold cranking amps (CCA). While popular brands often make consumers feel safe in a big purchase such as a battery, it can also drive up the price.
Remember, popular and more-expensive brands become popular for a reason. Users have found the brand to be the best product for the price and have recommended it to others. And consider this: There is a difference between low-cost car batteries and cheap car batteries. A cheap battery doesn't cost much, but it also doesn't give you much. In the end, buying cheap battery after cheap battery instead of investing in a more-expensive, longer-lasting one can end up costing you more money.