The easiest way to purchase Akash Tokens ($AKT) is to buy Cosmos tokens ($ATOM) and swap your $ATOM for $AKT using a decentralized exchange (DEX). From there you can send the ATOM to a Keplr wallet and use Osmosis to convert it into AKT. For currently supported tokens in Osmosis visit check the token types in the Osmosis web app.
Funding your network account is required to use the network. All messages charge a transaction fee, deployment leases are paid by the account used to create them. There are a two ways to fund your account, buying tokens and applying for awards from the community.
Tokens may currently be purchased on exchanges listed here. From there you can send tokens to your Akash account address.