I’ve a cyclops MAG for sale, £100 posted,
I used it while i was getting over a knee OP and couldn’t seem to cope with the extra movement required to ride on the road. Barely used th elast couple of winters though so not worht the space.
Never felt the need for a power meeter, most trainers are fairly linear in their resistance so as long as you keep the trainer in the same settings then just set up your cycle computer to measure the speed of the rear wheel, OK the results aren’t in Watts, but you’ll seee any improvement/worsening.