Well.... My official thought is, if you like it then you found an awesome value!
Originally I thought you might be curious what I would think of a $3 wine. Again, refer to original response. But in terms of general quality of super low cost wines, one has to think of the fixed costs of bringing a bottle the the shelf and then realize what is left to pay for what you're actually drinking. After the profit for the store, profit for the winery, shipping cost, labeling cost, bottling costs, cost of the bottle, the cork etc. How much of that $3 is actually left to pay for the grapes/wine itself. Not much. I'll post a picture below that is from Europe, but illustrates the point. For folks that are looking for a super market wine, there tends to be a large difference in quality between a $5 wine and $15-20 because most of that added cost can go to what's actually in the bottle. The same is true in reverse for ultra high end wines, but that's a different discussion.
In terms of sulfites (not sulfates), the general consensus is that isn't what is causing headaches most of the time unless you truly have an allergy. In which case you would also get a headache from other foods that have sulfites. You guys know I'm sure, often the reason is simple dehydration and people not treating wine like any other alcohol and making sure they're getting enough water with it. The other causes are actually tannins or histamines. Red wines have tannins because the tannins are in the grape skin and they are fermented in contact with the skins (thus the red colour). The only way to avoid that is if you're sensative to tannins, avoid red wines. Aged wines can histamines believe it or not. One response the body has to histamines if you are sensitive is headache. One way to check that is if you know of a wine that gives you a headache every time you drink it, just take a Claratin before having it and see if it still happens.
Now, why did this wine not give a headache? Who knows. Maybe Sir Easter Hair was drinking more water than usual. Or, being a very inexpensive wine, the red colour was obtained through dye and not by being in contact with the grape skins so there was little tannin. Yes this happens and more with cheap wines. Or this wine was aged for about 45min before being bottled, so histamines weren't an issue.