Do you really need so many GTIN codes?

I’m selling sports clothing and am having trouble coming to terms with how many GTIN codes I’d need to buy. I have about 20 products, each with variations for sizing, colors, gender, and left/right handedness. Just one of my products has 44 unique variations.

I have a brand registered with Amazon, can I get around the need to spend thousands of dollars on just GTIN codes?