GST on purchasing and selling of goods.

I am a wholesaler but my total turnover is less than Rs 100000 and I have not done GST registration.. At the time of purchasing I have paid 12% GST. So now came to the question.... Let Rs 140 be the MRP of a certain item. For that I have paid Rs 100 and 12% as GST charge. Then total amount I have paid is Rs 112 i.e. my cost price is Rs 112. The same item I have sold to a retailer with a Rs 2. So shall I can charge GST or not. If I can charge GST, then at what amount I can charge GST i.e. at Rs 100 or Rs 112 or Rs 114. Kindly clear me the concept.