Vacuum sealer and reusing commercial packaging bags?

I recently bought a silly gadget at a friend's urging: it a little gadget with heating elements so one can reseal plastic bags. I'm not yet able to use it well -- i don't consistently slide the bag through the little sealing gap and occasionally burn holes. But i expect i will be able to with practice.  It started me wondering though if a "real" vacuum sealer would be able to reseal the bags from commercial cereals and a variety of products.

If you use a vacuum sealer, have you tried reusing the bags that come with cereals or boxes of crackers and does it work? I'm less concerned about the vacuum part than the sealing part, but happy to hear about both.

(Brands and attachment recommendations welcome.)

I have a vacuum sealer like that (mine is a FoodSaver); it came with so many and a roll of cut-to-custom plastic that I have never tried to use other bags.  I think it could ruin the machine, though.

The bags that come with it seem to be constructed in two layers; an outer smooth layer that does not melt, and a hatchmarked inner layer that melts and seals together.  I expect that if you tried to heat-seal an ordinary single-layer bag either: 1) the plastic would not melt at the temperature of the sealer, and just would not seal or 2) the plastic would melt and get stuck all over the heat-sealer and basically ruin everything.  

I don't really like using so much plastic and try to reuse the heat seal bags as much as possible.  Like with frozen berries I cut the bag open just below the seal, use what I need, then re-seal the now smaller bag.

I am about to begin cooking rye berries and then pressure cooking them in polypropylene bags.  I am a little nervous about using the bags, because I have read that they can melt or tear, but it seems that many people are able to do it by packing them in the pressure cooker a certain way.  I am trying to learn as much as I can about the process before I begin.  I just thought I would share that, as I was in this forum looking for tips.  

I have not been successful with cereal bags.  I have successfully resealed some commercial bags. Those that appear somewhat thicker work better.