Question about Era

To get my 6* Rotta, I had to spend 78k crystals (13k x 6), that ended each week with the toon at ~10/100 shards. I would need to spend another 10-13k on shards per toon to get them to 7* . So now you're at 138 - 156k crystals for just shards. To get the mats to go beyond 114, you would need to drop real money and that total price I'm not sure of. 

You can buy 15710 crystals for 140$ Cdn (before tax), so 1400$ just for shards if you dont partipate in literally anything. With taking 1st in fleet, dailies, events, 34-36* TB and winning in K2 GA, I was able to get 13k crystals between each toon release. There was only wiggle room to refresh 3x for conquest, so no refreshing for relic mats. That would cut it down, so 840$ Cdn (140 x 6) for shards. 

I'll take a wild guess and say 400$ for mats, that hopefully is overshooting by a lot, but still. So 1240$ Cdn before tax would be my guess to get a 7* DJJ. 

6 characters for $100 each, a 3-month pass for $40, and materials to upgrade 6 characters to Era level from 110 to 125, along with the calendars, came to around $180–$230 — I don’t remember exactly. Total $900-$950.

p.s. And I also have Rotta at Era level 132, which corresponds to relic level 7 after the Era ends.

I'm not sure anybody can answer that without knowing how many crystals you expect to be able to spend on characters during the Era.  You can significantly reduce the costs if you have around 20k of crystals to spend per marquee.  Google AI will probably help you evaluate your options so you can formalise a plan.