I'm normally a pro-coating guy but here's the thing, with a Jeep, assuming that you might actually go mudding and the like, you're going to have a lot more physical abrasion than other cars. A coating in this case won't do too much for you. Mud is basically dirt and water, so if you're mudding then you're kind of dirt blasting your paint. Even a coating won't last you a long time, basically cut down the durability by about half if not more depending on how often you go mudding.
I would suggest you stick with what you are already doing. It's a lot easier to just re-apply a coat of sealant after a wash of a muddy jeep than re-applying a coating every year or less. I'm pro-coating but that's because to me, if it won't last at least the two year mark or over, I don't see the point.
Now if you're just driving it as normal, by all means coat it. The others have made good suggestions over what coatings to use, use a reputable one.
A free detailing in my opinion is worse than no detailing. I'd rather my car be dirty than let a dealership touch it, period. The shop maybe independent but if the dealership is paying them, I can guarantee it won't be great rates.
A professional grade coating might do you well but you're looking between 1000 to 3000 depending on the product used. The choice is yours. However if it was my jeep and I was driving it as a daily driver, then I would go ahead and look at CQuartz UK. Best consumer level ceramic coating I've used so far.