Get a Garmin FR60 with HRM ($94) and then buy a GSC10 ($38). If you later decide to get a GPS, you'll already have the HRM and Cadence sensor so you can buy the cheaper GPS bundle that only has the GPS. Even better, if you are lucky you might find a discontinued FR50 for $50 with HRM!
Prices based on internet searches, but I don't get paid to recommend any particular vendor.
Best thing about this is that setting up the parts is easy-peasy and you can download your data into a computer or up to the internet for later perusal.