Truck keeps shutting off now will not crank

Several days ago, my battery light came on. But the truck didn't run any differently so I didn't really freak out about it (my trac and VSC light has been on for months). I want to say the light didn't stay on, but I don't really remember. A day or so after it had first come on, I was driving along and the truck starting kinda sputtering (is the best way I know to explain it). The radio cut off too. But as fast as that started, it stopped doing it, truck kinda jerked and started acting right. It only lasted maybe a minute. Maybe less. Well a day or so after that happened, I had went to the store. When I went to leave the store, it did the same thing then started acting right. So I kept driving heading towards Walmart. I got to about a mile up the road and it shut off. I coasted into the gas station right next to Walmart. Truck wouldn't crank. Some guy stopped to help me and I had him jump me off. I didn't get out of that parking lot before it shut off again. I was able to coast into Walmart shopping center. I called my daughter to have her come jump me off. Well about 10 minutes later and before my daughter could get there, I tried to crank the truck and it cranked right on up. I drove over to Walmart parking lot and went in. I was in there about an hour to an hour and a half. Came back out and truck started with zero problems. So that's twice it's cranked without having to be jumped off. I left Walmart and got about 2-3 miles and the truck shut off. I coasted into a parking lot. I had my sister in law come jump me off because it wouldn't crank. I sped off (didn't even cut my lights on at night) and got about a mile and it shut off. I coasted into another parking lot. She came and jumped me off again. I got about half a mile and it shut off again. She followed me and jumped me off again. At this point we were just trying to get it back to my house. I got a little further up the road before it died. She tried to jump me off several times but it wasn't happening. It won't crank but as soon as you took the cables off, it shut off. I caught a ride home and left the truck in the middle of the road. My sis in law then took my husband back to the truck. So the truck sat about 10 minutes. He messed with the terminals and she jumped him off and he got home with no issues. He cut the truck off and let it sit then cranked it back up. We had zero problems for like 2-3 days. He informed me that we don't have a brace or whatever that is holding that battery in place. So when driving, it's kinda sliding and jumping around. Obviously, that is going to start to mess up the connections. So this morning, on my kids first day of school, I was headed to take them to school. Got to approximately 5-6 miles and battery light came on. Again, truck wasn't doing anything out of the ordinary. Once I went about 5 more miles, the battery light went off. I was able to get kids to school (another 7 or 8 miles further) and get all the way home with no problems. Immediately after getting home, I had to leave again. Shortly after cranking, the battery light came on but didn't act up. About 6-7 miles later, it started to die. Ij popped the hood and moved the battery back over to where it is supposed to be, kinda messed with the terminals and truck cranked. But then it shut off. I had someone jump me off and truck ran like a dream. About 30 minutes later I had to go some places. I made it a good 15 miles or so before the truck died. Wouldn't crank. Took forever to get someone to help me. Finally got jumped off and came straight back home. Not 30 minutes later, husband called and j had to go pick him up from work. He works about 8 minutes from our house. Truck cranked and drove fine. After driving down that terrible gravel road to get him, truck died when I got there. He moved battery and messed with terminals and had it jumped off (by portable jump box thing) and good to go. Got a little way down the bumpy gravel road and shut off. He did the same thing and good. We went about 10-12 miles and were good. He had to go in a place and left truck running. About 5 minutes into it being parked and running (with AC on full blast), it died. I jumped it off with jump box and it cranked just fine and sat running for another 5-10 minutes. We left to get children from school and drove approximately another 15-18 miles and the battery light came on and truck started to shut off. Took a minute but got it cranked by jumping it off with jump box. Got about half a mile and it shut off again. Finally got it cranked after trying numerous times to jump it off. We had to park and go in and get kids instead of going thru the line and we cut the truck off. Once we had kids, we went to leave. It cranked with no issues after sitting for about 10-15 min while getting kids. Got just up the road and died again. By this time, the jump box thing wouldn't crank it. Well it would but wouldn't stay cranked. I had a guy stop and try to jump me off, but as soon as you take the cables off, it shuts off. My husband was pissy and we didn't want to take up this man's time since he had his kid in his truck so Chris told him it was okay and we had someone coming. My sis in law came and got us but truck is still sitting there. We've been told it could be the alternator. Or the connections on the battery or several other things. But we don't know what it is and don't have a lot of money or means to get it fixed. Need help! Sorry for the lengthy question but I wasn't sure what facts may actually be relevant or could help someone figure out what's wrong!