Oil change

Hi guys, I have done my oil changes since i got the truck right out of the dealer, i think i am wasting a lot of money changing the oil every 3,000 miles, even though the it recommends every 10,000 miles. should i start using full synthetic? heard for only a few more bucks i could get double the miles before my next oil change, and if yes which one should i use? I am confused on the recommended ten thousand miles oil change that is on the truck system, it seems like a lot of miles to put on before my next oil change. Is that for regular 5w-20 oil or is that for Synthetic? I am still doing my oil change at three to four thousand miles on regular oil. Also, do you guys recommend I change into Synthetic and change at seven thousand miles or stay with regular oil? Really need some advice. Thanks for your feedback and have a good day Thanks for any information you give me.