I have looked into the costings for the "RiverInvertebrate Monitoring For Anglers". A one day course, held by the river fly partnership.
The workshops are designed for up to 12 delegates from one angling club. The course covers an introduction to monitoring, targeting species, (Up winged flies, Caddis or sedge, Stoneflies and shrimp), feild work and establishing a monitoring programme.
The cost for the one day workshop is £1000, that does not include venue costs and AV equipment. That cost has to be found by the angling club or sponsor.
There doesn't seem to be a monitoring course for an individual to attend, although I only had chance for a quick scan of the site.