Tim at Keen's Reef has some calibrating solution for 1 a bag. You will eventually need them to calibrate every couple of months so you are better off buying some to save.
I am pretty sure Tim is going to the meeting tomorrow so you can always ask him to bring some so you won't have to drive so far.
Yeah, and if you call Milwaukee, they may send you some. If you bought it new, it should've included some. Also Cap Bay and SWC sell it if you aren't going to the meeting.