I am in a similar spot my boys are in scouting and Florida gets some cold weather and we avoid summer camping. I got lucky and got 2 nice 40 degree bags mummy bags at an auction that were brand new. My oldest is fine even down to the low 20's with good layering, thermals, sweat pants an long sleeve shirt but my youngest is more likely to be cold. I got him a suisse sleeping bag that's rated for 20 from our Kmart going out of business sale. In warmer campouts we just take to 40 degree bags and use them as cover sleeping on camp pads. My youngest also loves using a hammock with bug netting when its warmer. We do a lot of car camping drive to the spot and camp or canoe to the site and camp so weight has not mattered much but we just started backpacking and now I am looking for myself a lighter sleeping bag. I got an alps mountaineering 0 degree wide as I am not small and its great for car and the canoe but it does not pack down and weight right at 8 pounds but it sleeps warm and I have had it down to 20 degrees on a dock in a swamp in the open air. I would find out from the scout leader what kind of camping they do and buy accordingly. Look for great deals online and locally. I got all of us 65 liter backpacks from amazon for more than half-off last year. My tents I got from Kelty on a discount end of the year sale. The troop may also have some loaner gear for them to start out in as well and have him ask some of the other scouts about there gear.