150 would require 3/4 w a 1 piece top if going over 5' in length. 1" would give more piece of mind. Hope you have DEEP pockets. No such thing as a good price on acrylic sheet. And if you're looking to have it cut, machined it's going to be VERY expensive. In the city you have Canal Plastics. Online you have tapplastics.com or Eplastics.com
And again, regardless of size it will not be a cheap project.
Technically I need 2 pieces ,48 x 96 ($ 429.71, if I pick the right stuff, I mean the right Acrylic, close to 3/4") from one I can cut two 24 x 60 (front and back) then I got left over for side 30 x 24 (minus Saw blades +Router) then from second sheet I need one piece for bottom 31 1/2 X 60, I have a shop were I can work (make jigs , glue etc.) will be around 187 Gal. so $ 1000 + my work , will be just fine. The only one concern , is, NOT sure if I can make 90 degr. (perfect) ?!