I have this one on Beeman P-17:
https://www.amazon.ca/gp/product/B06XD8 ... UTF8&psc=1 .
To me dot itself is a little bit big, looks like more 4-5 MOA, but bright enough for outdoors. Sighting this red dot takes some time with hex keys, but it works and seems to keep zero.
Another red dot I got is Bushnell TRS-25, I used it on SKS for some time, but removed it and put on Benjamin Trail air pistol. This one is good quality for the price and survived already a few years on Benjamin Trail so I suppose it's lives on springer (or nitro piston to be precise). Besides you can regulate red dot brightness, so dot won't completely cover target. Cheap red dots normally don't have auto shutdown, so you always need to remember to turn red dot off when you done with shooting.
If you're willing to spend a little bit more I think Vortex red dots are good. They have unconditional lifetime warranty and I've seen Vortex Crossfire on sale for $150 at cabelas.ca.
If you have a rifle maybe it worth consideration to buy a air rifle rated scope, so you can nail really small targets. For my TR-5 rifle I bought UTG 3-9X32 Bug Buster scope, I think I paid something around $150 for it some time ago. Works well to me, keeps zero and you can be focused as close a 10 feet. A lot of scopes die fast on spring air rifles due to specific recoil and can be focused starting from 50m, so keep that in mind.