Tee Shirt T-SHIRT Designs - Looking to develop 400 Designs in Total

I am looking to develop 400 T-Shirts designs in total.
I will provide design examples and your job will be to make the examples betters in Typographical Style and or Graphics themselves.
I am looking for a fixed price on the total designs.
It should take about 15 minutes per design to develop as I have the template and the design styles are simple.
Examples attached.