Ok I need to use Modiferes to sell 3 different sizes of each item I have listed on my website.

At the moment I have to make 140 modifers, 1 for every product, simply because all prices are different as they go up in size.

Is there somehow I can adjust price with a % instead of a $.

If not, is there a way I can do it,is it going to be implemented soon.

Thanks

Maybe you can try variant attribute instead and override variants' price.

Please follow instructions in quick start guide. I suggest you go through the tutorial before working on your own site.