I just checked the price of embossed bags has come down to 20 cent a piece for the 20x30cm size (good general size). Don't know about retail stores in UK but Amazon seemed to have a bit better prices than Ebay sellers. Like £15.77 w/ free P&P for 100pcs 20x30cm bags.
If you're using a roll, find out what size bags you need and how many, and make them beforehand. Don't try to make the bags too small, you'll just ruin the seal (liquid "contamination" or bag not being completely flat in sealer unit because it's stuffed too full). I do things in following order:
- cut the meat
- wash and dry my hands
- prepare the bags by double folding the mouth (protects the seal area from getting wet)
- stuff the bags w/ using only one hand to touch the meat (again to protect the seal area of bag)
- wash and dry hands again
- undo the double fold
- vacuum and seal
- prepare for freezer by marking and e.g. making the minced meat bags flat so they're easy to store and fast to defrost (sp?)
I tried to find an image or video but no luck. I try to explain, bear with me...can I ask what you mean by double folding ?