Yes it is generally easy to fix. Get a manual for your truck and then buy the part and replace it yourself. It is an afternoon job, if you don't know what you're doing, and it iwll save you money and give you more satisfaction than touching parts of your face with your tongue.

thermostat very easy
 

Generally speaking the thermostat repair job is one of the easiest. Generally it involves removing a hose clamp, prying off the hose. Unscrewing two bolts, removing the thermostat and reversing the process. The trouble is knowing exactly which hose, so its good to have a manual. First guess: the large diameter hose going directly from the engine to the top of the radiator.

You might as well flush your radiator at the same time because 1) you're going to lose some fluid in the process, 2) you really don't know the thermostat is the problem in this case, 3) you said its never been done in 8 years. The anti-freeze and the water pump lubricant in the water has a limited lifetime. I'd say its much less than 8 years.

Bad news: the coolant fluid is poisonous to pets (I've read cats like the taste) and is terrible for the environment, so any lost fluid should be captured and recycled (take it to any place that does oil changes and the like). So you're asking, "How do I catch all that water and transport it?". There's the rub, so you might want pay someone to do a professional cooling system flush. My guess about 80 bucks at an independent shop. If that's over your budget, I'd start by putting a large bucket under the radiator and remove the plug. That should catch the bulk of it. Then every time you remove a hose some may also spill out that didn't drain all the way through, try to catch that, too. Then liberally hose down your drive to dilute anything that you missed.

PS: My school didn't offer stuff like "auto mechanics", I learned from my dad and my friends. Its always good to know a gearhead.