Those seem like good prices. Soaring at my club is pretty cheap, IMHO, about $240/year dues. Each tow costs $17 to 2K', and the rental fees go from $6 to $12 per hour.
Most annuals cost about $100 on a glider. It helps that there is no engine. And, in a club there are often volunteer IA's to do the work and inspections.
Sometimes a club will have a commercial ride operation that helps to subsidize the maintenance. Our operation also subsidizes a junior program quite extensively, until they solo each flight costs them $3. A good investment in the youth both for the good of society, and the long term health of the club. We have former junior members ranging in age from 19 to 80.
A commercial glider operation is much more expensive. However, it can be a much more efficient way to knock out the ratings. Depends if you are in a hurry or not. Helps to take advantage of the social aspects of the club and make friends with the instructors.
-- IFMU