with very little effort one can google up bags with similar enough design, materials, etc. at closeout prices.
many of the name backpacks have lifetime guarantees; I have mountainsmith bags that have been returned for newer, beefier zips; totally user abused goods, fixed for free.
if all you do is disc golf, by all means buy a $200 bag meant only for disc golf.
if you're just a burnt out old cynic with an aging, washed out hound and you only need to carry 15 discs, a cell phone, a 3 liter camelbak, an ipod, garden seeds, hat, gloves, rules, pencils, minis, flashlight, leash, and trash bags, then you should feel free to buy nearly the same thing for $45 on ebay.