That "trapped" feeling is just awful. 

I bought it in a Black Friday sale and in a huge bit of coincidence, my car battery ended up not starting the same day my package arrived (my first battery problems in several years)!  Unfortunately, I was not home when my battery problems happened.  I had to get a ride share home and then back to where my car was the next day with the starter but it worked well.  I'm not mechanically minded at all but it was easy to use.  Just connect the two cables to the battery and the car started almost immediately.  (After starting, it's best to drive the car half an hour or so before shutting off the engine so the battery can get fully charged again).