First thing is to KEEP IT SIMPLE. kids are not in need of the fanciest gear they just need something that will work, is comfortable, and of course it helps if they like it ! (get their input). Its nice to get the gear local where they can actually try it on in store but online can be more convenient depending on your situation. To save money you can ask family and friends if they have gear that would fit. Growing up my cousin would give us a lot of his old hand me downs. I loved it because we always looked up to him and I thought I would play better in his cleats ! Start with the basics : ball, cleats, shinguards. They will outgrow quickly so its good to get the shoes right before season starts to ensure they fit properly throughout season. A gearing up for season page parents guide was just recently posted on the home page these show current recommendations for making the decision process a little easier.
For Ages 5-7 start with a size 3 ball if you can. Once again most cheap balls will be able to still last a while. Older kids usually opt for shinguards without the ankle guard but I think its a good addition for the younger ages ensuring they stay safe around their ankles.
Also get creative at home a large cardboard box or laundry basket can serve as a mini goal. Water bottles can be little cones to dodge or to try and kick over. The more times they have played with the ball before their first practice the more comfortable they will be. Even better if they can get in a couple practices with a friend or a small group before their team training starts. Being in a big group for the first time can be intimidating. Encourage them always and have fun supporting them. I wish you the best – Coach T$