I have a $50 red dot on my 44 mag and my 50 cal Vortek pistol. The one on the Vortek is a Center Point . The one on my 44 is a Tasco. I had people tell me they would not last but both have. I have put close to 100 rounds through the 44 with that sight and it hasnt come off center. 30-40 rounds through the Vortek with the same results.
If you want pictures let me know.
The dot sizes are measured in MOA. The smaller the better for a small animal. The smaller the dot, generally the more expensive. I think both of mine are 5 MOA.
If you got a 5 MOA dot and shot at 50 yards, the dot would probably be bigger than the body of the squirrel ( dot size would be about 2.5 inches). A 2 MOA would be better (dot size about 1 inch).
At the price of the 5 MOA red dots it might be worthwhile to pick one up and play with it to see if it meets (meats!

)your needs. Once you figure out where the bullet hits within that circle you may be able to hit a squirrel 2 out of 3 times. If you only shoot at 25 yards you may be just fine.