1994 Blazer hitch 5.7 4x4 1/2 ton
 

What brand would you recommend and how to be safe? Towing a camper for 2.

Any of these two brands will work for you, Trusted brands and competitive prices on this site:

1994 Chevrolet Blazer Trailer Hitch | etrailer.com

You could also call up your local UHaul and see what they have to offer. I wouldn't buy a used receiver from someone or a brand I'm not familiar with, and I sure wouldn't go with a homemade one from a buddy.