Need help, truck won't start.

Ok I have a 2005 trd off-road Tacoma. I bought it used with around 50,000 miles or so. I've had it since march of last year and I now have 77,000 miles on it. I never had and problems but today I go to start my truck in the morning and it's fine. I stop not 5 minutes later at the store. And when I start it up again it made the sound when your batterie is dead but it kicked over and started. Finlly went to work about 3 miles away stop and turned off my truck. About 20 to 30 minutes later I went to stated it but all I heard was the batterie clicking. Had my buddy try and jump my truck with his but still nothing. It almost kicked over but it didn't. We checked my batterie and it's still good. What else can it be and why do I need to do to fix it. If you cam help please do.

 

Starter selonoid it sounds like man. If you know what your doing you can get under and jump from the positive side of the selonoid to the other side and if it cranks. thats your prob. But only do it if you know what your doing, cause my might get a nice little shock if not. Grab an old screw driver.