If you don't have any problems with buzzes or other noise in your system now, a power conditioner would be a waste of money. If there is no noise, there is nothing to "condition".

You should however always have a surge protector feeding your equipment. This can be nothing more than a simple outlet strip which uses a metal-oxide-varisitor (MOV) to protect against high line surges from electrical storms. They can be bought inexpensively anywhere like Home Depot.