logo design look in

i need logo design my colours for my company is yellow and blue ok and name is computer clinic i would like a medical cross with sum sort of computer related to it so its like a cumputer doctor as we do computer repairs. i will not pay money upfront but will look at sample designs then pay the one i want and chose that as the winner. i will need for letter head and at high res for shop logo banners please send sample in private message thank you