I have not shopped much at Costco, but I have shopped a lot at Sam's over the years and personally, I do not think it is worth it for groceries. My husband gets a membership to both through work and he loves Costco for things like tires, big ticket items, etc. It is not convenient to me to go there for groceries. If you had a really large family and needed to buy in bulk, then maybe Sam's or Costco would work, but I found most items at Sam's to be MORE expensive than Walmart. Like at Sam's you can get two large bags of name brand chips for $7. Big deal! They are regularly on sale at Walmart for that or less and I don't have to buy two bags when I only need one. Yes, you can buy a huge container of Heinz Ketchup for much cheaper than the same quantity in smaller containers, but do you really need, want or have room for a huge container of Ketchup? Do you really want TWO family size boxes of Cheerios? (My husband believes that when we have bought in bulk on items like toilet paper or paper towels, that we tend to use them less conservatively, because we have so much.) You really have to bargain shop and compare the prices. You cannot assume that Costco will be cheaper on most items. But you also have to consider your time and gas, so you shouldn't be going to three different stores to buy everything. I have found Walmart to be the BEST deal on most items and they will honor other stores sale prices. Most grocery stores have door busters on certain items like soda or ice cream, but make up for it on other items. Take the store flyers that you get in the mail and Walmart will honor those prices plus take coupons. I have been really pleased with most of their store brand items also, which are much cheaper than name brand.
Shop at Thrift Stores, Resale Shops, or Garage Sales for kids clothing, toys, etc. You will be amazed at some of the deals you will find. When my husband was unemployed and my kids were babies, I would shop garage sales to buy all of their toys and clothes for next to nothing. Then I accidently discovered Thrift Stores and am hooked on them. It is harder to find things for older kids, but especially for little girls, there is usually a lot of nice things. I even began buying stuff for me and my husband! My kids were always well dressed, even when my husband was out of work, because of this. People would compliment them all the time on cute outfits and I would just smile and think, "I only paid $2 for that outfit!"
Insurance is a gamble. We went for several years without any insurance and we were lucky. We have never met our deductible, so it seemed a safe bet. Then we got a policy that had a very high deductible, but was much cheaper monthly. It was just basically a safeguard for a catastrophe. That is a personal decision that you have to make. You might also need to consider the new Health care stuff. I am not up on all the ins and outs, but it could be that if he is uninsured for several years, he will not be able to opt back into private health insurance and will be required to do the National Healthcare. Just something to consider and check into.
Please remember that this is very devastating to your husband and his ego. For most men, more so than women, their self worth is tied up in their job. He is very likely to go through some depression and difficult times. Try to be encouraging and supportive. It is hard, because there may be times when he seems to be goofing off or not doing all he could to get another job and you will be very frustrated. Hang in there! Avoid making comments to friends or even to your husband about having to save money - just do it and don't through it in his face on a daily basis. Best of luck and hopefully he will be employed again soon!