score:5
Here are some techniques. Unfortunately the best ones require either knowledge of Russian (or a Russian-speaking friend, hostel employee willing to help, etc), or skillful use of Google Translate:
There are many "Groupon-like" sites in Russia, selling gift cards for various activities. They tend to be city-specific, so I can't point you to specific sites. Search for "подарки активный отдых (city-name)" or something like that. These sites list a lot of sports activities at reasonable (local) prices.
Once you find an activity you like, see if you can find the website for the operator of that activity. The trick here is to realize that many small activity operators don't have real web pages, but instead have pages on the VKontakte (vk.com) social network. You usually don't need an account to access these pages, and they often have prices listed, direct cell phone numbers for the operators, etc.
Try asking people on CouchSurfing in the city you're interested in to help you find and book the activities. Many Russian cities, even small ones, have active CouchSurfing communities, and there may be people there speaking your language. Just make it very clear that you're not looking for a place to stay, just some help with the language and perhaps someone to show you around.
Ask around in good hostels
Upvote:0
Different prices for locals and foreigners are (or were) common in state museums, because it is assumed that we locals sponsor them with our taxes. As for the sport activities, they shouldn't be priced differently. After all, even having separate web sites with different prices won't work if you use Google Translate to read the Russian version. So just search online, maybe using automatic translation.