The SLIP^2 workshop registration is free.
When registering for the workshop via the ICCAD portal, it may appear that there is a fee. However, the fee will be incurred only if you also register for ICCAD at the final stage of the registration process. So please proceed with the registration, and on the last page do not select the ICCAD virtual conference. At the bottom of this page, you will see the selection button for SLIP^2 with no cost.