When your children are picked to participate in school sports, ask if there is a payment plan on their sports uniforms. So rather than having to come up with the big lump sum all at one time, stretch the payment out so it's convenient for you and your budget.
My son has played football for 8 years and is currently playing JV football in high school. My husband is a coach for the youth football league so I have faced the cost of spikes, etc many times. Talk to other parents, they may have used gear they can't use anymore.