If money is tight, just get a standard wired speedometer. It'll have a clock function on it, it'll keep track of miles and speed, and a single 2032 battery will last for years, no recharging necessary. I have never had a HRM watch; so I can't comment on how they work. I do have a Garmin 500 and I use a standard HRM chest strap with it. It works fine, but the head unit needs charging every ride or two; which can be inconvenient when I go on week-long tours.