TON Indexer is a lightweight, self-hosted server that helps users easily track on-chain transactions and access blockchain data more efficiently than directly querying the blockchain. It is designed to index and store transaction data to facilitate quick and efficient access.

Now, let's address your additional questions:

1/ Latency difference between TON Indexer and the TonCenter API:
The exact latency difference between TON Indexer and the TonCenter API can vary depending on factors such as server resources, network conditions, and query complexity. However, since TON Indexer is self-hosted, it usually provides lower latency and faster access to the blockchain data compared to a centralized API service like TonCenter API, especially when the self-hosted server is in close proximity to the user.

2/ Cost to run TON Indexer:
The cost of running TON Indexer as a personal lite-server depends on the hosting environment and resources allocated to the server. Users can choose to host it on their local machine or rent a virtual private server (VPS) from a provider. The cost will vary depending on factors such as the provider, server specifications, and data storage requirements. Generally, the costs for a VPS can range from a few dollars to tens of dollars per month, depending on the selected plan.

3/ Basic requirements for running TON Indexer:
The basic requirements for running TON Indexer include a server or a computer with adequate processing power, memory, and storage to handle the indexing and querying of blockchain data. The exact requirements will depend on the volume of data and the number of concurrent queries the server is expected to handle. Additionally, the server should have a stable internet connection to synchronize with the blockchain network.

It is also essential to have a compatible operating system (such as Linux) and any required software dependencies installed on the server. To ensure smooth operation, users should follow the installation and configuration instructions provided in the TON Indexer GitHub repository.