How and where to buy in bulk?

Been into peptides the last few months and they worked great so far, especially the reta. However, as you all may already know its a really expensive habit... im wondering how I should fare if I want to buy in bulk? Obviously the short answer is some pretty lady from China (joke) but where do I find reliable vendors? WhatsApp and telegram seem so sketchy to me. I live in northern Europe also so bare that in mind!

Any help is appreciate!