Graphic Designer - Cartoonist required for poster/marketing campaign

hyper local app (connecting people with similar interests eg. basketball, cricket, dance, gym, same company, flat and flatmates etc.) - require creative and innovative designers to design posters and android screen design. Would have to submit a sample(watermarked) before I finalize. If sample is selected, would be paid for the sample as well. Sample: Home screen with just 2 buttons: Sign-in via google and sign-in via facebook. This would be the first page user would see once s/he would open app, so lets be creative. It could be as simple as a logo with these 2 options or more complex.