When I order or buy seeds, I often buy in bulk. This is not only cheaper for me, but since I garden year around, I always have seed on hand. No need to make a special order. But buying in bulk means that I need to store the seed in such a way as to preserve its quality. Otherwise the seed will deteriorate, not germinate, thus wasting my money. I've been there, done that, and don't plan to waste anymore money.
Some companies package their seed in sealed containers, preserving the seed better. But most send the seed in paper packets. I transfer seed from paper packets into sealable glass containers. The idea is to control the humidity/moisture exposure to the seeds. For large seed I will use appropriate sized canning jars. Their lids make a good seal. For small seed or small amounts I will use glass test tubes with rubber stoppers. Again, it's a real moisture resistant seal. I used to place a desiccant in the jar with the seeds, but unless it's homegrown seed, I don't bother anymore. The commercial seed seems to be dry enough already.
Once sealed in glass jars, and of course labelled (at my age I don't trust myself to remember!), I store the seed in the refrigerator. I have a chest refrigerator, so I store seed at the bottom where the temperature doesn't fluctuate.
For homegrown seed, I store it in a jar with a little desiccant. I started out by using powdered milk. But when I mentioned this to a medical lab person, she said that at work they threw away desiccant packets all the time. So she started saving them for me. Now I have plenty, in fact at my age, a lifetime supply! A friend in a floral shop told me about the desiccant they sold that had an indicator crystal in it. When the crystal changes color, it's time for it to be dried out again (an oven works great for this). So I've mixed the two together giving me plenty to work with while still having the benefit of indicator crystals. I've been told that you can buy desiccant online, but I like the idea of re-using something destined for the trash. So when I want to add more desiccant to my stash, I can ask my local medical clinic or veterinary hospital to save me some packets from their medical testing kits.
I haven't tried using my freezer for seed storage. For one, seed needs to be dried down more than just natural-dry for safe freezer storage. I couldn't just pop my homegrown seed in there and expect everything to be fine. And second, I have room in my frig for seed storage, but not my freezer, which is often crammed. Plus my system present works for me ok. My seed does just fine.