I understand proc spells are expensive nowadays because no one really farms them and they are mandatory for seal ptys, but people can either take the time to farm those spells they need to farm the gil to buy the spells they need just like back in the old days. If a spell costs you about 500k on AH, then maybe join a cruor pty or even an exp pty if you can't find a cruor build pty and get yourself about 200-300k cruor and even that can be turned into 500k or more gil. I really don't think it will take you more than 6 hours in one day to do this and in the end it'll be worth it.

If you're too lazy to do the above mentioned then perhaps it's time for you to lvl another job like a thf or something where you don't need to spend a lot of gil on mandatory spells.