Passes don't get discounted, but roughly every 4 weeks pass ufos fly around, where you get a free amount when purchasing at least 1000.

The ufo passes come every weekend friday you get and extra 1000 for every 1000 passes you buy and then I think saturday is 500 and sunday is 200 or 250 I cant remember exactly

they do not come every weekend. i think it's usually the last weekend of a promo. usually once or twice a month depending on when the first one ocmes.

Also for Christmas and some other event months they come out with special packs! Usually you get good deals on the passes in them and they come with either a divine or a companion. Last year I bought like 5 of the cheap Christmas packs since they came with Hanabi.

Thank you very much all of you for your answers! Very helpful <3