[Fab] Acrylic buying recommendations

[noisebridge at encambio.com]

Hello list,

I'm trying to get started with the laser, and don't have any acrylic
to cut yet. I'm using acrylic to make boxes like the kind on
Makercase [1].

[1] http://www.makercase.com/

It seems McMaster Carr and ePlastics are two online vendors of
acrylic (extruded and cast) that have good selection, but I'm
not sure about postal orders. Is that how most of you get your
acrylic?

Are there places in San Francisco in reasonable (public transport)
distance to the Noisebridge where I can get acrylic without waiting
for the post?

Thanks,
Michael