There are a few national distributors for acrylic. Farco Plastics, Commercial Plastics, and GE Poly Preforms to name a few.
I've priced them all and still get my best pricing for the quantity I can afford from framing distributors. If you are ordering what you think is a significant amount of product, ask for better pricing.
If you can afford a truck full, talk with Cyro.
Edit: I posted while Jim was posting, and there can be advantage to buying the Cyro/TruVue product. The packaged sizes typically cost more per SF, but may be more efficient usage for framing application thus saving money. Depends on the size of the frame.