Backpack liner

You can spend $35.00 and buy a nice flouro orange bag liner from a sports store or go to the supermarket and buy the same bag labelled Garden bag for $1.00. Personally what's written on the outside dosnt bother me.

you can get big plastic pack liners from shops that are usually around the $5-$10 mark i think which are huge and do a great job and can be used as an emergency shelter if you get into strife.

A dead dog bag from the Vet's works great ,you can get them in a couple of sizes (depends on the size of the dog) I've had mine for years

I love the "dead dog" bag!! I just use one of those medium sized domestic green rubbish bags - buy them at the supermarket - works great for a trip or two. I only use a 35 liter pack (Macpac Amp 35) and travel real light.

I personally do not use a liner. I did for a while because there seems to be a lot of talk about how wonderful and indispensable they are. I have found them to be a pain. I am sure they have there merits. I use small bags to pack everything in to my pack together depending on what they are and what the need is. All my clothing is dry and safe. I carry a large 1.5 m by 2.7 m rubbish bag as an emergency shelter, be no use as a pack liner. It takes up very little room, and yes, I have used one in the past to keep my sleeping bag dry when caught in a storm. For me, the back pack liner is not a must have item, but if you must have one then a bin liner works fine. Just a tip here though, the green reusable eco bags that supermarkets sell for about a $1 each are great in huts, tuck a couple into the pack and use them in the hut to keep your gear tidy and out of the way.

Two things spring to mind 1/ I have yet to see a pack that was water tight. 2/ When you get cramp in both legs while river crossing on your own a bag liner ensures that the pack is in fact a big inflateable raft to cling to rather than quickly sinking lead weight full of water

A pack liner is handy if you have to pack up and carry a wet tent -- you can leave it on the outside of the liner.

I'd agree with Haqii above, I'm no great fan of a waterproof liner, it just makes it more difficult finding things. I use a combination of sealable waterproof bags, and cheap super market bags. Even in the wettest conditions things stay dry.

make-shift rain coat, rubbish bag, store wet gear, fill holes in walls, emergency blanket if you buy one big enough, Hang food from the roof, Bring home a cut of meat when you are offered it by a well meaning hunter, I could go on but for about $1 its about the cheapest handiest thing in a walkers kit