New to medical: Can I get my prescription and take it anywhere?

First timer here (not to cannabis - the medical cannabis system). I had a consult with Calyx Clinic, process and doctor was great, very easy and professional. But I might have jumped the gun: I didn't realise they have such expensive flower, and I'd like to just get my prescription and be able to take it to another dispensary, even Chemist Warehouse if that's an option? Can someone help me out with how it works please? Am I restricted to getting buds through Calyx since they are the ones who've prescribed me? (I imagine that's how they make their money seeing as it was only $50 for the consult) Thanks for your help!