If you don't have the zip lock vacuum bags you can just close the bag except for the last inch then submerge the whole bag except for that corner. That will force out the air and you can finish sealing the bag.
This product was given to me by my husband for my birthday along with the mushrooms he picked when he went mushroom hunting. When I checked the internet and found how to store these mushrooms, they suggested washing them and freezing them in bags. After washing and cutting up pounds of mushrooms, putting them in the Ziplock Freezer Vacuum Bags really made it kind of fun. It was like working on an assembly line and before we knew it, we were all zipped up. After bragging about how nice and flat they will store and how they fluff up after you open the bag up, our friends and family were taking our bags with them. I bought a few for gifts and have now started my kids in the habit of "zipping". They are great for storing bricks of cheeses which taste better and cost less than the shredded types. I keep the bags and vaccuum in an easy access drawer and hear it being used frequently. I love it for the veggies like peppers, onions and lettuce which usually go bad if not quickly used. It is great for bulk ground beef and stores the meat flat in the freezer and has an area for the date. Great product.
I recently purchased the Ziplock Vacuum bags with a coupon that I had. I wasn't sure how well these would work but I was impressed. The pump really did get all the air out of the bag. The first bag I tried though wouldn't seal right. There must have been something wrong with that one because the other ones I have used worked great. As far as freezer burn is conserned, my food hasn't been in the freezer very long so I don't know how well they will hold up to that.