The same seeds are same seeds! Example: "A-Train" can be bought from several seed banks, but they all came directly from TH Seeds. If there are different prices for the exact same strain, buy the cheapest one. They are the exact same seed.
The breeder creates and packages the seeds (original breeder packs). Not the seed banks. There are slight price differences between banks, but usually not that big of a difference. Make sure you're seeing the same qty in both packages.