This gets covered all the time.
Look at this from the point of view of a sponsor with a unknown team, unknown players, limited if any experience in tourny ball who want discounted or free kit, training etc. Who in their right mind would sign up for that.
You have to be able to give the sponsor something back. There are 2 main ways of doing this advertising them and/or their products this can be done in various way but obvious ones included selling space on your team jerseys, the other main method is being really good with a certain product say you being top of you division and favourites for the next division up would give you something to backup you up so when peopl watch you play they wonder what kit has been helping them to get their. For example Dynasty, the top team in the world, are sponsered by many people including Smart parts and NXe both of which have had alot of growth over the past few years because the consistently best team in the world uses all their kit.
So to sum up their is no such thing as a free lunch offer the sponsor something they would want and they might be able to help with say discounted prices.