I got quotes in that range as well here in boulder, so I installed one myself a week ago in about 2 hours(aprilaire 700 - $310) with no special HVAC knowledge, though I am mechanically and electronically inclined.

I haven't checked the electricity usage but I can't imagine it is much. The system is literally just a small fan and a solenoid valve. Maybe your parents opted for a steam system, whereas mine is called a flow through style.