DeFiChain (DFI) is the native cryptocurrency of the DeFiChain ecosystem, which is designed to facilitate decentralized financial services. The token plays a central role in the platform, serving as a utility token that powers transactions, applications, and incentivizes user participation. Here are some key ways DFI is used:

1. Transaction Fees: DFI is used to pay fees for network transactions and smart contracts, ensuring the smooth operation of the DeFiChain ecosystem.

2. Staking and Governance: DFI is used for staking purposes, where users can participate in the validation of transactions and contribute to the network's security. Additionally, DFI holders can vote on governance proposals, shaping the future of the platform.

3. Collateral: DFI can be used as collateral for borrowing assets on DeFiChain, allowing users to leverage their holdings for further financial activities.

4. Wrapped Tokens: DeFiChain's decentralized token wrapping feature allows users to wrap other cryptocurrencies like Bitcoin, Ethereum, or ERC-20 tokens, increasing their utility and enabling more investment opportunities.

5. Decentralized Exchanges (DEXs): DFI facilitates crypto atomic swaps in a peer-to-peer manner, ensuring users retain custodianship of their assets and minimizing risks associated with traditional exchanges.

Overall, DFI is the backbone of the DeFiChain ecosystem, enabling a wide range of decentralized financial services and incentivizing user participation through staking and governance mechanisms.

To store DeFiChain (DFI) tokens, you can use DeFiChain wallets, which are available in various forms:

1. Light Wallets: These are non-custodial wallets with a 24-word key. They are suitable for users who interact with DeFiChain regularly and provide easy access to DeFiChain's features.

2. Desktop Wallets: These wallets have a physical wallet.data database and a passphrase. They are also suitable for frequent users and offer a higher level of security.

3. Cold Wallet Alternative: While there is no native cold wallet for DeFiChain, you can create a cold wallet-like setup by using a backup phone that is disconnected from the internet. Store the majority of your DFI tokens on this offline phone and use a second wallet on your main phone for trading. This setup provides a higher level of security, but it is still not as secure as a dedicated cold wallet like Ledger.

In summary, DeFiChain offers light and desktop wallets for storing DFI tokens, and you can also create a cold wallet-like setup using a backup phone for added security.

To buy DeFiChain (DFI) tokens, you have several options:

1. Centralized Exchanges: You can purchase DFI on centralized exchanges like KuCoin, Bitrue, or Gate.io. First, sign up and register an account on the chosen exchange. Deposit the cryptocurrencies you want to use to buy DFI, such as Bitcoin or Tether. Then, navigate to the DFI trading pair (e.g., BTC-DFI or USDT-DFI) and place your order.

2. DeFiChain's Decentralized Exchange: You can also buy DFI through DeFiChain's decentralized exchange (DEX). First, download and install the DeFiChain Wallet from the official website. Deposit the cryptocurrencies you want to use to buy DFI into your wallet. Then, navigate to the DEX section in your wallet, select the cryptocurrency you want to sell and DFI as the one you want to buy. Confirm the transaction to complete the purchase.

3. Trusted Partners: Another option is to buy DFI through DeFiChain's trusted partners like Cake DeFi. Sign up for an account on Cake DeFi, deposit your cryptocurrencies, and then withdraw them to your DeFiChain wallet. You can then use these funds to buy DFI on the decentralized exchange.

4. Kriptomat: You can also buy DFI using Kriptomat, a platform that allows you to purchase cryptocurrencies with a credit/debit card. Create and verify your account, add funds, and then select DeFiChain from the list of available cryptocurrencies to complete your purchase.

Each method has its advantages and disadvantages, so choose the one that best suits your needs.