Reading some of the OP's posts I get a distinct sense of panic. I'm wondering if I am picking up on that correctly.
Ma'am Do you mind if I ask how long you have been thinking about prepping and what it is that you think is going to happen? Is it going to happen next week?
I hate, with what is only my second post on here, to go against the grain, but I feel like hitting the breaks a bit on what seems to be a very frenzied thread. I feel like you have expressed both an extreme sense of urgency and a small budget. You will not find that those two things go well together.
In the time I spent on this subject my plans have changed many times as I continue to learn more. For every prepping need there are at least ten different ways to prepare. You will read "this" and think it is something you have to have for your family and later find "that" and realize it would have been cheaper and or more efficient. I want to point out an earlier thread were you mention going shopping and starting a red BOB and not being able to remember all of the items you had put in it, but that they were all very important.
I advocate that you take a few deep breaths and read, read, read, here and everywhere else. Then sit down and start forming a plan. I know there is trouble on the horizon, but I'm pretty sure we're safe for the day.
As for the hubby just let him know you've decided to start being more thrifty since prices of his most cherished foods have been going up. watch for a sale on something and buy a case instead of a can. It makes good financial sense, and if you end up with a stock pile of it, well who can complain when it was such a great deal and it will get eaten and enjoyed even if SHTF never happens. Consider being a Coupon clipper. If you have seen that show extreme couponing or what ever it was called you will see people with huge basements full of food and supplies and they don't even consider themselves preppers! Anything you can rationalize rather than hide will be for the better.
Bow hunting with your son sounds great, especially since he expressed an interest on his own anyway.
gardening is a great hobby that does not come off as crazy. Oh, and if you happen to have a bigger crop than you expected, well why not take up canning and save your own vegetables rather than buy them from the store? I'm sure you husband would not want them to go to waste, only to have to buy more from the store throughout the winter!
Have you ever looked at a garden the day after it rains? It is so HAPPY! gardens love rain water much more than tap water, so it makes perfect sense to have a rain barrel or two around the house to use to water your garden. If you water supply is ever lost and you need the barrels to collect drinking water at some point in the future, why that would be purely coincidental, he could never fault you for that, nor would he if he was thirsty.
you and your son could start taking walks, then hiking trips, then hiking trips with big packs on. gradual is good for your fitness development and good for masking you true purpose as well.
Keep a full tank of gas in your car at all times. If he asks why, it is b/c if the tank gets low water can condensate in it, or the sediment in the bottom of the tank can get sucked into the fuel pump and trash it.
you get the idea.
Don't implement all of these changes at once or it will be to fishy, and again today is not D day, you don't have to do it all at once.