Steering wheel vibration in 98 honda civic


Hello, I am considering buying a 1998 Honda Civic LX with just a little over 91,000. My concern is vibration in the steering wheel that is present when breaking and when driving at low speeds (but seems to dissipate somewhat on the highway). A mechanic I just saw said he believed the cause was due to all 4 tires definitely needing replacement. Also said he did not suspect the alignnent. Does this sound right? Could it be something more costly than tire replacement?