Being that I sell triathlon training products I've been very actively supporting the various clubs and organizations. Often, they will add backlinks to your site and sometimes do a little write up on your service. Most importantly though, you could get customers and visitors for little to no cost. It's win-win for everyone!
I look up triathlon clubs and organizations and then offer them sponsorship and/or a discount. If they accept, they usually post a logo or text link back to me. Also, I may get some business. They get some money or a coupon code. We're all happy. So, for those that may provide information or a service, there may be a club or group out there that may be interested in you. That includes business groups, sports clubs, support groups, etc. I actually use the <search term> site:.edu to search for clubs at universities and such.