Non-profit organizations may be eligible for a free SketchUp Pro license. To qualify, you'll need to provide proof of your non-profit status and demonstrate how you'll be using the software for charitable purposes.
Trimble (the company that owns SketchUp) offers a full, unrestricted 30-day trial of SketchUp Pro. You don't need a credit card to start it, but you do need to create a Trimble ID.
A credit card is not required to start the trial, and it will not automatically charge you when it expires. 2. SketchUp for Schools (K-12)