The first thing you need to consider if the load. Face it most of usd are in the shape that if it goes much beyond 25 pounds we ain't going to carry if far or very fast. So a high tech super bag is overkill.

Sure if you are using a bag on a regular basis you need something that will last and last. For this kind of thing it doesn't need to be that rugged. Mot of those cheap kiddy daypack/bookbags will work. I'veseen them on sale for less than $5.

You could also try a thrif or goodwill store. You might find a bargin. There are also yard sales.