What is the legal amount of money that a landlord/manager can ask from a new tenant when signing a lease? for example, is it 1st and last months rent? 1st months rent plus another amount of money for a security deposit?
It depends on your state law. Some states don't address the issue at all, in which case they can charge anything they like. You can find your state landlord/tenant law listed on the sticky note at the top of this forum.
While i am sure some states have laws on this, i am pretty sure in most states it's what the market will bear. In other words what ever they want, but if it is too much no one will want to rent the house.