RptView by Pursuit Technology was originally for sale. Then it was free with ads. Now it has now been released as a free viewer without ads. All that is required is that you register with the vendor. To see what it can and can’t do you should read my annual comparison of viewer applications which I updated this week to include this new information.
If you don’t have CR installed you can view any report simply by double-clicking the rpt file. Alternatively, you can launch RptView and then identify the folder that contains your reports. Keep in mind that RptView is no longer being actively maintained. If you do need support, you can hire the vendor to fix any problems you find.