The wounds you're seeing are only on the surface, there is probably more severe damage on the inside. Please, do whatever you can to get your kitty some help. He desperately needs it.
if the wounds are oozing that means they are infected and kitty needs an antibiotic. I know money is sometimes very tight, but if you want to save this kitties life you are going to have to try ....phone all the clinic's and see if they will set up a repayment plan of so much a month with you...Otherwise I'm not sure what else besides peroxide can help him...If you cannot do this than maybe call your local animal shelter to see if they will take him and get him the help he needs....good luck♥