I have a 6-speed which has had some issues shifting smoothly for the last 80k. I armchair diagnosed it with bad synchros. I already know what caused it. My dad drove the car while I lived in the mountains and I needed four wheel drive. He had the same seat setting as me even though he's 4 inches shorter than me, leading to him not putting the clutch all the way in on SEVERAL occasions. If he ground gears multiple times with me riding in the car I'm sure it happened the entire 2 years he had the car. That's neither here nor there, but I have just been living with the rough shifts for the last 3 years when I got it back. Anyway, recently I've noticed the clutch is slipping when I get on it. I've been babying it for the last 5k, and I could probably get away with another 5k. My question is:

How much is a transmission rebuild running these days? I figured times have changed since the last time I had one rebuilt on an old car.