In the context of the Ethereum blockchain, 'Gas' refers to the computational efforts required to process a transaction or run a smart contract (automated contract). The concept of 'Gas' is unique to Ethereum and is not used in Bitcoin. So as you use these systems more, whether you're sending money, receiving it or doing other things with a smart contract, you're using up 'Gas'.
The Gas Price is not fixed and can vary based on a number of factors:
The total transaction fee is calculated as the product of Gas Price and Gas Limit, where Gas Limit is the maximum amount of Gas a user is willing to spend on a particular transaction. This helps to prevent runaway conditions where a transaction would consume an unfair amount of resources
For example, if the Gas Price is set to 20 Gwei (1 Gwei = 0.000000001 Ether) and the Gas Limit is 21000 (standard for transfer) then the total fee comes out to 0.00042 Ether.
Unfortunately, no. Gas is inherent to the operation of Ethereum and similar blockchain networks. It's a way to prevent spam on the network and to compensate miners (people who maintain the network) for the computational power they contribute. Without a mechanism like Gas, the network could easily get overloaded and slow down.
However, with a clear understanding of how Gas works you can make informed decisions on what kind of Gas Price to set and possibly save some money in fees.