Not sure if everyone knows this one, but the uniform supply store across from Valley Med Center on Bascom Ave in San Jose offers a 10% discount to students.

And, this online store seems to have some great deals as well: http://store.yahoo.com/allheart/index.html

There is one more chain that I personally like a lot and that have huge sales time to time. You can buy pants and tops there starting from $10. Check out online sails as well
Their website is
http://www.lifeuniform.com/LifeUniform/
The closest location is across the Valley Fair on 2475 Forest Ave.
San Jose, CA 95128
Phone:(408) 244-3445

Hours:
Mon-Fri:10-7
Sat:10-6
Sun:12-5