With all the political turmoil going on at home, it would seem people would have alot to say about Caesar rampaging through Gaul, gaining allies and wealth, and using up Rome’s resources on what must have been a costly war. Did any prominent figures if the time have anything to say about this? Was his war popular, or frightening? Did the average person on the streets applaude the conquest, or did they even know about it as it was going on?
EDIT: I guess what I should be asking, to get more to the point I’m looking for- What sources do we have which describe contemporary Roman opinions of Caesar and his Gallic Wars?
Boy, if we knew the answer to that we might have some inlking as to how the de bello Gallico was published. We have no idea how the text was published. Pretty much all we do know is that the final version of the text must have been completed sometime after 52, but we don't know if it was published in pieces as the war went on. Hirtius' addition to the text, Book 8, must have come after the de bello civili was published and sometime before Hirtius' untimely death, but since we know even less about the publication of the de bello civili (if that's even possible) that leaves us nowhere.
But are you asking about the de bello Gallico's reception, or are you asking about the campaign in Gaul? Cicero commented on the campaign in Gaul, he even wrote the de provinciis consularibus on it. Cicero also gives us our only comment on the reception of the de bello Gallico and the de bello civili (he seems to know about both in the Brutus, c.46), in which he says that although Caesar wrote them to serve as aids to historians he did such a thorough job of it that nobody feels it's necessary to do it himself. Also:
using up Rome’s resources on what must have been a costly war
Do you have some reason for thinking that A) Caesar was eating up money from the treasury and B) that the war was costly? I'm not aware of any session of the senate that voted money from the treasury to the war in Gaul after the initial levy in 59/58. He confiscated the treasury in 49, but that was after the civil war began. Presumably the troops were being fed with grain being levied from Cisalpine Gaul, Caesar's province, as was usual in military provinces. And while across the Alps Caesar's troops lived off the land, which he says Vercingetorix took advantage of. Provincial warfare was typically very profitable, and while occasionally extra money was requested from the treasury (though such requests were, as Cicero shows in the in Pisonem, looked on with skepticism) to finance a campaign, usually campaigns seem to have paid for themselves. There's no indication the Gallic campaign was any different.