branding my products on amazon seller

so i just launched my products in amazon in generic brand. now i have a few questions.

right now i dont have budget to register for trademark or brand.

i was told by someone i can sell my products under a brand name even though by not registering. i just have to send amazon pictures of my products with my brand logo and i would be allowed to sell with my brand name. so i just want to know if thats really possible?