There is about three quarters of a mile of free fishing on the tidal section of the river Otter at Budleigh Salterton. This is between the lowest two bridges on the river (the upper one of the two being a foot bridge). It cannot be described as wilderness fishing, a very busy footpath runs all along the river here and it is overrun with grockles.
At the other end of the scale the Deer Park Hotel at Weston near Honiton will sell you a day ticket for the Otter for £30, which to my mind is a rip off.
The Otter above Honiton is a good little brook in places but most of it is taken by syndicates.
Angling 2000
http://www.angling2000.org.uk/ have a beat on the Culm near Collumpton which is cheap enough but I have no first hand knowledge of it.
Tight lines
Andy