Chrysler Sebring 2000 Seat Belts locked. The average cost of repair?

I own a 99 Sebring JXI conv. and my seat belts work sporadically also. I found out that because it is a convertible the seat belts(front only) are controlled by a solenoid located under the center console. These are notorious for failing in this model of car and are quite pricey to fix. I can make mine work most times by moving the position of the seats. Mine has 217K on it and not worth putting a lot of $$$ into so I just deal with it for now. I'm having a time of it right now with my brakes. I replaced front pads and now there is a hissing sound from behind the brake pedal when you step on it and it goes all the way to the floor. I hope it isn't the brake booster 'cause that may end my time with this car. Good Luck!