I bought a pair of Thermacells before our last trip to Alaska, and after the supplies for them run out, the devices are history. They run about 50 cents an hour to operate. What they are is a small hand held catalitic heater that runs off of disposible propane mini tanks, then you put a treated "card" into it and the heat drives off the chemical into the air. When I am our on a fishing stream for 8 hours, then sit around the campfire for another 4 hours, I have spent about $6 for supplies. Too much in my opinion. If the slightest breeze comes up, it blows the chemical downwind, of if the breeze is varitable, it takes a bit of moving. Plus there is a warning on the Thermacell devices not to use them in enclosed spaces such as RVs, or tents. Now anything I can't use in a tent, I am not sure I want to be breathing.
Many years ago I bought a case of military surplus Jungle Juice, almost 100% DEET product and am finally down to the last couple of bottle. That stuff works, but it also disolves plastics, gun finishes, fishing lines of some types, sunglasses, etc.
But I am a bug magnet, have tried all the food items from garlic to vitamine B-12 without much luck. My wife loves to have me around when we are camping as nothing will bite her if I am close by. We were up at Disney World's Fort Wilderness this past weekend and the yellow flies feasted on me, receiving 8 or 10 bites before I knew it and I have a bad reaction to those guys. About the same reaction as I get from the bites of the white sox gnats of the north country.
So I will stick to the DEET products, especially the new Off one that goes on in a powder form, not oily at all. When camping we use some of the larger sized buckets of citronella candles with the 4 wicks per bucket and set in the center of the four buckets.