How expensive to farm 86 shards in mace Windu? Tips?

Month? Yes. Easily. When the Yoda event was announced, all I had for Mace was one single shard. I decided to put all my effort towards ulocking him ASAP, so my daily routine now is to spend all my Cantina energy farming his node (you get 120 energy daily and the node costs 10) plus I buy one refill using the crystals I get from dailies (every 3-4 days I have enough to buy 2 refills). This allowed me to unlock Mace with 2 shards to spare this morning. So I got him in what, 8-9 days or so?

However, if by "month" you mean "this month's round of the Yoda event", you'd have to spend cash on crystals to buy refills for the cantina. A lot of refills. With 5,5 days left in the event, you'd need around 16 shards daily. My average is 7-8 using 240 energy.