The choice of a customized Data Availability (DA) layer in Polygon CDK chains significantly impacts costs. Using Ethereum's mainnet for DA ensures high security but incurs substantial fees due to on-chain data storage. Alternatives like NEAR or Celestia DA layers drastically reduce costs—NEAR claims up to 8,000x cheaper than Ethereum—by storing data off-chain while maintaining reliability through Data Availability Committees (DACs). Validium mode, leveraging off-chain storage, further lowers transaction fees compared to rollup mode, balancing cost and scalability. Developers can tailor DA solutions to specific needs, optimizing for payments-focused or high-throughput projects. This modularity enhances efficiency, with NEAR and Celestia integrations enabling faster, cost-effective transactions, fostering scalability within the Polygon ecosystem.