IF the owner (or his property manager--whomever you rented from) knew at the time you signed the lease that the property was for (or was about to be for) sale and did not disclose that fact, you would likely have grounds to void the lease without penalty for fraud and move out; you could also likely recover out-of-pocket costs (e.g. additional moving expenses) you incurred due to this failure to disclose a material fact. If the plan to sell was made subsequent to your leasing the property, however, you would likely have no grounds to void the lease or seek monetary compensation.In any event you have to cooperate with efforts to sell (the owner has a right to show the premises), but do not need to allow anyone in the home but on proper notice (usually 24 hours or more) and at reasonable times--so the realtor and clients cannot simply enter at will. You are, after  all paying for posssession of the premises.You have no right to block the sale. If anyone buys the property, they buy it subject to your lease (assuming you did not void it): that is, the buyer becomes your new landlord and the lease stays in effect.