Understanding the basic fee for blobs.

Janak9955

EIP-4844 operates according to the following pricing rules:
If the number of blobs in a block exceeds the target (currently set at 3), the base fee for blobs increases.
If the number of blobs in a block is less than the target, the base fee for blobs decreases.
If the number of blobs in a block is equal to the target, there is no change in the base fee for blobs.

In addition to this new pricing mechanism, Type-3 transactions will still have max_fee_per_gas and max_priority_fee_per_gas fields and will be subject to the constraints of the existing EIP-1559 market. Apart from blob space, Type-3 transactions still need to pay for the EVM space they use.
Blob is expected to significantly reduce the cost of deploying to the Ethereum mainnet, leading to a shift in the L2 market. Many in the ecosystem predict that in most cases, the base fee for blobs will be close to the minimum level.
However, this introduction will bring new complexity to L2 operators, who now need to decide between using Type-2 and Type-3 fee mechanisms to aggregate their transactions on-chain. Sometimes, regular Type-2 batch transactions may be more expensive than Type-3 blob transactions, and vice versa. Therefore, each L2 must monitor two separate markets to determine which market is more favorable to use based on current network conditions.
It is expected that L2 may not need the entire blob space, and there may be L2 time-sharing studies: 1) waiting and fully filling a blob and/or 2) coordinating with other L2s to share blob space.
The Dencun upgrade and EIP 4844 bring new opportunities to L2 networks but also present Ethereum with more observable challenges. As Type-3 transactions enter the market, L2s will need to manage the new opportunities brought about by these changes.

Sona59

It's important to understand all kinds of fees.