Hey Marcus,
Welcome to the forum. If you are new to callmaking, get your process down with wood first. It is more economical. If you insist on acrylic, Kelly at Midland Plastics will treat you right. My advice is not to buy casting resin at a hobby store. (It's more complicated than just mixing and pouring) Your finished product will be subpar.
Read everything you can here on the forum, especially the tutorials. A lot of good stuff on YouTube also. Ask a lot of questions. And most of all, have fun with it.
Troy