Charitiy T shirt design

I am looking to create a design to be printed on the back of polo shirts for a charity event.
I need the design tone simple, eye catching and describe the event in simple terms and not be to busy and include - the name, foot prints and a map (outline and roads)
The name of the event is Sole Mates.
Id like 3 different designs to be created and have the option to pick a favourite and make changes until the 3 people involved have a final piece to be able to be printed.
I need this done as cheap but as good as possible as its all for charity.
Thanks for looking