HELP! Pace Tracker for running

nnm1976

I'm a treadmill runner and would like to take my running outdoors (now the weather is warming up), but I'm having a hard time getting my pace down...I can run 3-5 miles indoors but can't run 2 miles outdoors and I'm constantly feeling like I'm running too fast or too slow. I was wondering if anyone could recommend a good and affordable heart monitor/ pace tracker combination device. I've looked them up online but I'm always weary of reviews.

Thank you!