The prices at Specialty Bottle Supply are pretty reasonable if you order everthing at one time (although I don't know if this qualifies with you as a "more common source").(posted 8175 days ago)http://www.specialtybottle.com/
The most useful bottles are probably the "Ambers Bottles" and the "Jugs/Gallon Jars". Although they have few metric sizes, the 32 oz. bottles are actually 1 liter when completely filled, etc. Call or send them an email regarding higher quality reusable caps.