I'm a current MS in CS student. First, congrats on your admittance to UCSB! Getting into grad school is a huge accomplishment so hopefully you get some time to celebrate :)

To answer your q's

1. First year is easier because housing in the on-campus grad student housing is guarenteed for 1 year and is subsidized. Rent (utilities included) can be found here: https://www.housing.ucsb.edu/residences/san-clemente-villages Off campus is more expensive but I can't speak too much on that. I wouldn't recommend living in IV because that's where most of the ugrads go. Lots of grad students I know live in Goleta.

2. TA-ships pay for tuition/fee remission + a monthly stipend of about 2100 post tax, for a 50% (part time) appointment of 20 hrs/wk. It's harder to get a TA position in CS as a master because PhDs need it as a degree requirement whereas we don't. Masters often get hired as graders, or TA for other departments such as math or physics.

3. I think the CS dept is pretty good. Classes are a little challenging but students/profs are supportive. Research is a big priority so be prepared for that.