Figured I'd make this for any fans of huckin' frizz, frolf, discing, or just a nice relaxing round of whack fuck. Post away about your latest finds, aces, and PDGA hot gossip!
You could try using a rectangular cooler. A lot of people I know who only carry a few discs will use them. They usually hold a few discs, a couple drinks, and maybe a couple other items. Some companies make minimalist bags, too. I think Upper Park has a few and there is a company that makes a bag called a NutSac.
Infinite Discs, Dynamic, and some of the other big companies also offer smaller casual round sized bags depending on the style you're looking for. A lot of them are very affordable.
Thanks, the important part for me is that it is a basckpack. I bike a lot when playing and a backpack is the best option for that. Upper Park has the Shift but i can't get it in my country easily :(
Fair enough, depending on where you are at, a flat bottomed style backpack may work well for you, something like: Cargo Style Backpack
Look at fishing backpacks. Mine holds 2 large containers. Each is about 2 inches thick. So I’d say it could hold a stack 6 inches high. It has a water bottle holder. I got it off Amazon.
I ended up getting a Lat64 Swift because I didn't find this on the market and this was the smallest I could reasonably find, I just pack the empty space with towels and stuff to keep them from moving around.
If I wanted to go slim but still a backpack, I have a little Konami Sports Club backpack that barely fits discs snuggly, so you may just see what backpacks you can find that open with a top flap and just try fitting a disc in it to see if it works. I'd love to find an actual disc golf backpack the size of my Konami bag. 
I bought an Infinite Discs Slinger... It is a sling pack, not a backpack, but it has worked for me so far. I would probably prefer a backpack of some sort, but I dont have a ton of discs, and I am a big dude... so I feel like a backpack would be a waste of money, since the straps are never comfortable across my broad shoulders.
The Slinger is 25 bucks on Amazon, and while it lacks bells and whistles.. ti will carry a bottle of water, has a zip pocket for keys and wallet or whatever.. a mesh pouch on the outside i pack three or four discs in, then room for another nine or so inside. It also comes with a clip for a towel, or whatver you want to hang off of it.