For individuals who only wish to spare:
As long as you are a member, and the team you are sparing for already has paid for all four positions, you do not have to pay anymore fees.
If you are not yet a member and the team you are sparing for is fully paid, you have two choices:
Purchase a Membership outright via the Products tab on Curling I/O. This gives you all the perks and benefits of membership, including free sparing and access to Playmaker's.
Pay a $45 fee each drop-in spare.
Once you have paid this fee 3x, you will be considered a full member and will no longer have to pay to spare.
If the team you are sparing for has not paid for all 4 positions for the league:
Spares will cost $20 per game.
So for a drop-in spare who is not yet a member, the cost will be $65 up to 3x and then $20 for any subsequent spare.
If you are already a member, there will just be the $20 per game.
Extra Perks of Membership for Spares
When you sign up through Curling I/O, there is a spares list that you can put yourself on for each league. If you have your contact information listed, members will be able to contact you and let you know of opportunities to play.