How it started vs how it’s going..

PLEASE ANYONE ANSWER!!! I NEED HELP!!! my mum thought it would be a good thing to impulsively get a betta fish and has done nothing to properly take care of it and it's on the brink of death! I really REALLY want to get him the proper care he needs but I can't since i am very limited money wise (I am 14)... Now, he seems lifeless but isn't floating so I don't really know what to do... god.. I would give him the proper care in the blink of an eye if I could and I feel like I am going crazy knowing that I can't do much... All the thing my mum bought for him were just things that the stupid pet store employees said would be good for him(recommending a damn fish bowl was already a red flag) I know that he needs: 3 gallon tank, filter, heater, and a proper food source but I just need more information on how to help him with my limited sources. Literally ANYTHING will be highly appreciated but please don't get angry for how he has been treated... Me and my siblings just didn't know how to take care of it but we've tried are best and are willing to learn more and help him in any possible way. Thankyou... Sorry.

/r/bettafish Thread Link - reddit.com