Some tools need a prepaid wallet to run. It's a DEDICATED wallet for the tools, that you only use with the tools. So it must be a wallet different from you main wallet, and only filled with the tezos needed for your next few buys.
To use a prepaid wallet, you need to enter your private key, which is specific to that wallet address : IT'S NOT YOUR SEED WORDS. The tools will refuse any seed words. In Temple Wallet, you can reveal the private key associated to a wallet from the settings of that wallet. For other wallets, Google is your friend.
The Gas station allow you to see mempool transactions (aka transactions waiting to be processed by nodes) and see how much gas fee each buyer set.