Do employers have the right to reduce an employees wages without verbal or written notice?

My employer uses paperless accounting for wage payments in that the employees must have direct deposit of their pay checks into a bank account. In order to obtain a wage statement of taxes paid, garnishments, ect. we must use the internet or ask for a print-out of our pay receipts. Most of us do not have a computer and consequently no direct access to the internet. We have low wages ( less than $10/ hr. ) and can''t afford such luxuries in lew of paying bills. We have trust in our employer, however, I have recently gained access to the internet through a friend and checked on my wage statement and discovered that prior to December of 2011 I was earning what my employer and I agreed upon but then noticed that my wages were reduced since December 2011. I did not notice the reduction because our hours of work have been fluctuating since December 2011 until recently when I worked a full 40 hour week and did not receive what was the usual 40 hour payment to my account.