As is, the basic bag is $50 and will fit a jo plus a bokken with a tsuba. Standard features:
Double stitched seams
Double layered bottom
Sturdy one inch wide shoulder strap
The three most common add-ons are $12 each:
outside tanto sleeve, decorative print band, small inside zipper pouch
A pleated, drawstring pouch on the outside can carry several shorter weapons - from $20 - $30 depending on size/design
If you have a lot of shorter weapons, it would be best to consider a design based on the Dojo Bag.