Yeah, because you can instruct your retainer to look for and buy items at a certain price. So while the retainer is sitting there pimpin out your junk, he/she can be querying the system for like, fire shards at 150g and buying them all up if the retainer has the gil to do so. I think you can specify a number of that item you want to buy, so say if you only need like 20 fire shards, you can instruct your retainer, that once they have the gil, to buy 5 fire shards for 150gil whenever that opportunity hits the bazaar. I think.

If thats how it works, that would be pretty brilliant.