That's a bad idea. Inexpensive wireless computers have problems with interference from EM fields like you get from the eddy current sensors at traffic lights. A little time parked at "60 MPH" or whatever really throws off your distance and average speed.

The two reasonable alternatives are

1. Increasing your budget to buy a Garmin (I spent $150 on my 500). The ANT+ sensors are digital and either work (nearly always) or don't (I've only seen that when I'd bumped the speed cadence sensor so it rotated too far from the magnet). The price increase from an ANT+ computer to one with GPS and downloadable samples is relatively negligible.

2. Settling for wired. Wired just works and only means one battery to replace.