what kind of sealant to stop water leaks?

[hpcgmc]

I've got the water the glovebox, water down the kickpanels, water on the floorboards and even water dripping from the sunroof blues! I tried some clear silicone from Home Depot on the sunroof and it didn't work that well. The paint shop had a tube of 3m automotive stuff, but it was $22.00 per tube! What are you guys using to stop leaks in the roof drip rail and under the cowl? I've also got to seal the glass and the brackets for the sunroof.