To fund an AEA for testing on a test-net you need to request some test tokens from a faucet.

Add a private key to the agent:

aea generate-key fetchai
aea add-key fetchai fet_private_key.txt
or
aea generate-key ethereum
aea add-key ethereum eth_private_key.txt

Ensure the ledger apis are set in the aea config:

ledger_apis:
  fetchai:
    network: testnet
for fetchai or
ledger_apis:
  fetchai:
    host: testnet.fetch-ai.com
    port: 80
or
ledger_apis:
  ethereum:
    address: https://ropsten.infura.io/v3/f00f7b3ba0e848ddbdc8941c527447fe
    chain_id: 3
or both
ledger_apis:
  ethereum:
    address: https://ropsten.infura.io/v3/f00f7b3ba0e848ddbdc8941c527447fe
    chain_id: 3
  fetchai:
    network: testnet

Using a faucet website

First, print the address:

aea get-address fetchai
or
aea get-address ethereum

This will print the address to the console. Copy the address into the clipboard and request test tokens from the faucet here for Fetch.ai or here for Ethereum. It will take a while for the tokens to become available.

Second, after some time, check the wealth associated with the address:

aea get-wealth fetchai
or
aea get-wealth ethereum

Using the cli

Simply generate wealth via the cli:

aea generate-wealth fetchai
or
aea generate-wealth ethereum