Create 2d sprites for a mobile game

I am building a mobile game, but I have practically 0 design skills. I need someone to create some graphic assets which will be used in the base building aspect of the game. The player will be able to place walls, doors etc. I have already purchased some landscape assets, so I need these new assets to match the existing style, which is slightly cartoonish. I have included some examples. Initially, This job is to create : 1. Wooden wall tile 2. Include different states, eg, straight section, corner, cross, t junction 3. Matching door The tiles need to be in PNG format, and designed at 256 x 256 pixels. One I have found an appropriate designer who can produce the look I am after, we can then negotiate a price for the remaining assets that I need.