Need a Battery charger

How bout it. Had to buy a group 27 here recently. Alot more than I paid the last time.
Still trying to figure this one out.why did it decide to die right then and there?
The day of my mom's funeral.
The Durango started fine, no hint of problem when we left home. We went and picked up the monster in law, shut off and started there at her house just fine.
Got to the funeral home, just walked over to the Durango to head to the cemetery and...... Click.
Had to get a ride to the cemetery, and my son brought me back to the dead Durango, walked next door to the Napa and bought an (ugh) interstate battery. It's all they had. But I had no choice but to get that one then and there.
I had the same bad luck. Picking up my mother-in-law to go to my sons Wake. Driving my wife's BMW (Not mine) and it suddenly spits out the driveshaft. The light rumble it just started getting was what I thought to be a bad wheel bearing. :BangHead: