Yes, legally, you can. The software continues to work, only showing a nag screen for a few seconds on startup. Cockos relies on the honor system. Many users take months to decide or save up.
If you use REAPER past the 60-day evaluation period, Cockos (the developer) asks that you purchase a license. The pricing is remarkably budget-friendly compared to competitors. 1. Discounted License ($60 USD) reaper license key free
Most DAWs like Ableton Live, Pro Tools, or Logic Pro cost hundreds of dollars. REAPER’s pricing is revolutionary: Yes, legally, you can