This has been the simplest and most effective hacking I have ever seen. There are other tricks to vacuum seal foods, but they require more gadgets, time, or money comparing with this trick.
This vacuum sealing method is unlikely to give you as tight a seal as with a specially designed vacuum machine. And how well this method works depends on how well you have removed the air from the bag. But it is good enough for keeping most of your food fresher longer.
If you don’t like this method but prefer to buy a vacuum sealer, you can find some reasonably priced ones on Amazon here. Otherwise here comes the video tutorial for this great vacuum hacking.