My understanding is that the MAID COIN is a unit of measurement built into the network in order to give a comparative value of computing resources needed by the network.
The “value” of the coin in terms of something else like bitcoin, fiat currency (like the USD or British pound), or gold or whatever is determined by the exchange of MAID for that other item.
That valuation is called a market. Same as the farmers market, etc. Also applies to bartering. What is a person willing to trade in exchange for something else.
What is known as an exchange is a place (company/website for example) where they facilitate the trade of one coin for another or perhaps a coin (digital) for fiat.
So value of a MAID coin is dependent on what of amount money(value) someone is willing sell at vs what value someone else is willing to buy at.
Something else I have learned this week. “mining” is really a bunch of computers auditing a transaction and trying to all agree that the transaction is legitimate. A better term would be “auditing”. In bitcoin, the first to do so wins a fee.