1994 they were definitely still free[1]. I had so many good ones, but when they switched to the paid model[0] I was a broke college student and let them all go.

[0] IIRC, it was Unilever who caused it -- they mailed in something like 19,000 domain registration applications, one for each of their current trademarks.

[1] OK, I looked it up, September 1995 was when the charging started.