leaking head gasket :'(

[98Benzo]

So I was getting an oil change done today and my mechanic pulls me in the shop to show me that the head gasket is leaking....so I know this is a BIG job and seeing as my car has just over 200K on it so don't know if it's worth fixing. Is there anything I can use to put in the coolant to help prevent leaking for now? How expensive is a job like this? I took a couple pics will upload soon.

[98Benzo]

21782179

these are the two pictures i was able to snap real quick. Mechanic says head gasket is leaking...

[SD202]

you ever look at your oil or coolant? i bet it looks like a milkshake.

[98Benzo]

Have alwaysss changed oil every 15,000km and have done complete coolant flushes every 3 years...

[98Benzo]

Just checked my records and I did a coolant flush in March along with oil change and brake service...They didn't mention anything then. So could this be a recent thing?