Recommended inexpensive heart-rate monitors?
I can't speak about HRM's that do not use a chest strap as that's the only type that I have used (other than to play with in the store).  I find the ones with a chest strap to be completely hassle free, and I don't have to contort into a weird position to get a reading.

I've had great luck with HRM's from Timex and Nashbar in the $50 range, and like Polar but have never owned one.

If you do go with a chest strap type, the primary thing to watch out for in the lower-end range is the ability to change the strap battery.  Some have a sealed chest strap, so you either have to tear it apart and super-glue it back together, or replace the strap entirely.