Compuserve as an Internet provider
would make sense for 1994/1995 timeframe as would ITI2.net (registered for business April 25, 1995, verified offering unlimited dialup on a shared T-1 in 1996) but not for 1991. In 1991 the NREN was not available to the public.
It was the combination of the High Performance Computing and Communications Act
of 1991 and Information Infrastructure and Technology Act
of 1993 (42 U.S.C. § 1862(g) which legally opened the internet to commercial traffic in 1993) that resulted in the boom of small commercial ISPs such as ITI2, and Internet being added to various private online service providers.
did not offer general Internet
access (other than an email gateway since 1989) until they acquired Spry in 1994 (launched August 1st 1996), though that did not include any Compuserve access:Compuserve officials said a new business would be formed, possibly as soon as mid-September, to offer Internet services to commercial customers, including high-speed "T-1" leased-line Internet service, dial-up direct connection over regular phone lines and support for electronic publishing on the area of the Internet known as the World Wide Web.http://www.nytimes.com/1994/08/31/business/company-news-compuserve-to-offer-link-to-internet.html
A number of articles confirming the numbers I found in the archive. (At the time, AOL gave you your first evening hour free, then $5 per hour after.)https://www.google.com/search?tbm=bks&hl=en&q=Compuserve+1991+rate#hl=en&tbm=bks&q=Compuserve+Information+Services+1991+per+hour"List Price: Compuserve, $12.50 per hour (at 1200 and 2400 bps), $22.50 per hour (9,600 bps); 30 cents per hour CompuServe connect charge or $9 per hour 800- number charge"