SkySiteAudit is free, but crawling costs server time and bandwidth. Limits keep the service available for everyone and prevent abuse. The current values are on the pricing page. Counters reset daily (UTC). There is no paid way around them.
Fair-use limits
Why SkySiteAudit has fair-use limits, how scans and crawls are counted per visitor and account, and when the daily counters reset (UTC).