If you constantly use your seals then you can obtain whatever number of seals you can amass. How to obtain seals fast? Well you can do provisions for crafters and gatherers classes which gives at least 10k seals a day. You also can run run Expert roulette dungeons to obtain every piece of gear you can put your hands on which can be submitted to your GC for 900 seals each.

As for me I use lots of seals to obtain items for constructing my airships which normally burns my 50k seals quite easily.