How can i make my pitbull calm down (hes not small...)?

i go outside and he starts jumping up at me and wrapping himself around my legs harshly and just gos crazy and when i try to ignore he starts nipping hes a bout 1 year old i THINK.and everyone gives me tips like lay him down till he calms or ignore but hes strong not a little puppy so i would appreciate it if the tips were a bit specific because hes not weak and not really small.i rescued him from a family who was a bit abusive like hit him for no reason so i asked him if i could have him so i got him when he was already not small idk if that makes a difference well he is very difficult sometimes it gets to the point where im to nervous to go outside i know im not supposed to b nervous but i cant help it.IMPORTANT:i cant afford obediance training