@ms7dc I use Kaged Elite powder, two scoops in the morning in a shake with spinach, broccoli, strawberries, and banana, and another 2 scoops for lunch with pineapple, cauliflower, raspberries and blackberries. Keeps me full most of the day until dinner, but I also drink a ton of water during the day.
You don't want cheap protein powder though, it's full of all kinds of garbage that isn't healthy. Just compare the labels on the $19.99 protein powder you can buy at your grocery store with what is in the more expensive stuff and you'll realize how bad it is. Protein powder/supplements are really not a cheap habit either, especially if you consume a lot of them.
As for a wrist HR monitor, the Garmin watches are generally pretty accurate. I have a Garmin Instinct that I've worn for about 3 years now and it's within 1-2 bpm of my blood pressure monitor and chest strap whenever I'm running or biking. If you just want to use it while exercising, you can save money and just get a Polar or Garmin chest strap for under $100 on Amazon.