How can I get Review Units for my YouTube channel with below 100 subscribers?

Want to know how to get review units for a low profile YouTube Channel? Our experts will guide you on how to do it.

I have a YouTube channel based on Science and Tech with almost 60 subscribers. I want to review some products on my YouTube channel but I can't afford to buy products frequently. I wanted to know whether I can get review units From Flipkart, Amazon or Tradus and the way to get them under 100 subscribers.