I have a friend who gives me multiple copies of every insert. Of course he has first pick though. My next place to look is on ebay.com. The best time to find the coupons is the night the ad releases. I usually order most of the coupons I need at 12:30am on a Thursday morning. This is when my local Kroger ad comes out. If I can't find it on ebay, I will try Coupon Kutters. I LOVE THEM! I don't have to order 20 of the same coupon. I can order what I feel like I will use. The clipping services allow you to save time and money. You only get what you need and will use. Perfect!
Here is a list of my favorite clipping services:
You can also use these site to print off coupons. Each site will typically allow you to print off 2 of the same coupon per printer.
Also, make sure you use clipless coupons. These are where you can add coupons to your Kroger (or Kroger owned store) card. You can combine these with manufacturer coupons to make an even sweeter deal!
There are also yahoo groups that you can join to obtain more coupons.
I also write the manufacturers and ask them for coupons. You normally can do this every 90 days per each company. Most companies will send a high dollar or "free" coupon for you to use on your next purchase.
Hope this helps!