You dont have to use Real-debrid but it is recommend. Real debrid is a ddl service and Tor is a browser like chrome for those who really want privacy and anonmity, two different things. Plus tor is really slow when downloading. Regarding free to use, there are leech websites that leech off debrid services but do not allow torrenting or you can look for a trial version of a different debrid service or try a service like debrid-file.com that allow a lifetime subscription.