if you've only got 6 discs and plan to get more, you'll want to get a bag you can grow into. innova, discraft and gateway have some nice simple single shoulder strap bags with a drink holder and room for 12-15 discs. i have an old discraft bag that i used to cram 18 discs in that is still in great shape after 12 years. they're all around $25-50. with these traditional styles, be sure to look for the kind that have the ability to let you upgrade to quad straps (backpack style) straps later on.
if you plan to get a bit more serious, though, the recent surge of backpack style bags might be a better place to look. they've all got the bells and whistles that you're looking for, and they save your back if you wear them correctly. however, they're consistently double (or more) in cost what the regular style bags have been - upwards of $200-250!