The main reason they do it, IIRC, is because the banks handing out the landlords loans require some minimum rent prices on the leases in the loan contracts. The

The main reason they do it, IIRC, is because the banks handing out the landlords loans require some minimum rent prices on the leases in the loan contracts. The way they get around this is by offering a month or three of free rent. That way the leases signed by the tenants still me the contractual obligations of the bank. In the end the tenant still gets screwed when the lease comes up to be renewed, unless they are willing to move out over negotiating another free month in the next cycle.