I've had a Xiaomi Mi Band 7 for the past year and I like it a lot. using it with Gadgetbridge instead of the official app, so none of the collected data leaves my phone.

Check out the Xiaomi mi fit or Amazfit watches.

Wife and I needed the same thing and we didn't want anything fancy. We just needed to monitor heart rate and blood oxygen levels. Monitoring both these levels also allows you to monitor your sleep patterns which we liked.

I did my research and found the Xiaomi Mi Band 7 and the Huawei Band 7 … both are very basic, simple and straight forward watches with no bells and whistles but they are the only watches that can provide continuous heart rate and blood oxygen. Every other cheap watch out there that can provide heart and oxygen levels do so manually, which means every time you want to measure, you have to stop, turn on the setting and do a measurement. The Xiaomi and Huawei can be set up to just continuously measure throughout the day and log everything on your phone app … this is especially important if you want to monitor your sleep.

We couldn't settle on either so I bought one of each a year ago. I wore the Huawei and the wife had the Xiaomi. Both worked great and once they were set up we never had to monitor them … we could manual spot checks if we wanted to or just review the daily data on our phones. And most importantly it gave us the info we needed to do something about it sleep.

I work outside a lot doing carpentry work and renovations and I always wore the watch. My wife is not as active because of a chronic condition so she stays relatively quiet. After a year, her Xiaomi watch face fell off! Mine is still working fine. We had to buy her a new one as the warranty period expired. I offered to get her a Huawei but she liked the Xiaomi better … and for the cost, we didn't mind buying another one.

The only other thing that broke down for either watch was the rubber watch band … there are cheap easy replacements on Amazon and we just bought a bundle ($20 for 10 Xiaomi bands … $15 for four Huawei bands)

The battery life is about a week on both watches … and that's with continuous monitoring on! Just remember to clean off the contacts when charging because those get dirty fast.

Otherwise both are a great value and we enjoyed both. Huawei is a bit more expensive but more durable. Xiaomi cheaper but didn't last as long.

Like I said, you can get cheaper watches with similar features but these two are the cheapest ones that can give continuous monitoring.

I would question wether "good" and "inexpensive" are possible at all on a wrist tracker. Measuring your heart rate from the wrist is technically difficult - it's just too far from your heart and requires expensive sensors, a large battery, and even then a massive R&D budget (as in hundreds of millions) to get the software algorithm right.

Get yourself a chest strap - those are technically much easier to implement. You'll need to look at your phone to view your heart rate, but it should be accurate unlike most wrist trackers.

Even thousand dollar wrist fitness trackers (like the high end Apple Watch models) are often paired to a cheap chest tracker and those watches generally will trust your chest tracker over their own measurements - because even with billions spent on the best wrist tracker possible they still can't be as good as a $30 chest strap.

Look for one that supports the "ANT" standard. They will allow you to view your heart rate in real time on a variety of other devices (phone, watch, gym equipment, etc). ANT trackers just use bluetooth, so they won't send anything to the cloud (unless you pair them to a phone app that does that).

I've been using the Mi Band 3 for the past 4 years or so. Was about $15 new from aliexpress and hasn't broken yet - just the plastic straps which break every 12 months or so.

I've been pretty happy with the Garmin Vivosmart line.

Been using a Suunto 5 Peak watch since May and it's been absolutely great. Dunno if 250€ counts as inexpensive, but like we say in Finland, poor people can't afford to buy cheap shit that breaks right away. (I think they have cheaper options?) Suunto watches talk to phone app which at least on Android is pretty great, and the app can talk to other services which can analyse stuff further.

Apart from the Apple Watch (which became a door stopper when I moved back to Android) I've not had a lot of success with really good accuracy on watches. I actually opted to get a Polar H10 chest strap, and it is really super accurate. I usually live monitor the data on the Polar app on my phone (and it uploads to Strava, and then to Samsung Health), or if I'm outside I pair my Samsung Galaxy Watch to it with the Sporty Go! app so it shows on my watch.

Id look into this https://intl.cmf.tech/pages/watch-pro If memory serves it's like $60