All the transactions on micro account are made in cents. It means that if you deposited 1 USD to your micro account you will see it as 100.
Lot size in the micro account is 100 times less than on the standard account. It means that the cost of 1 pip will be 100 times less and your possible profits and losses are 100 less also.
We do not have any restrictions regarding the minimum deposit amount. You make decision by yourself what sum to start with.