Pistol scopes of any power other than 1x are hard to use because it is so hard to hold the gun steady enough to find the target. But it really depends on what you intend to do with the gun. Hunting ... scopes are OK if you can rest the gun on something. Off hand shooting ... tough to do as your shakes make the scope hard to use.
Red Dots give you a effective longer sight radius if they are the longer tube type and not the short open frame type. You will instantly see that you shake a lot more than you ever thought. But Red Dots allow you to keep both eyes open (retain 3D vision) with a red dot hanging in space over the target. They instantly reduce group sizes significantly over metal sights due to more precision sighting possibilities.
Cheapy Red Dots are a waste as they eventually fail due to the beating they take from the recoil of the gun. The best Red Dot for the least money, in my opinion, is the UltraDot (Larry's Guns) entry level one inch tube type with NO selectable reticules (dot size and patterns). The selectable reticules add complexity and all choices may not be aligned to each other making re-zeroing with reticule changes a possibility for precision shooting at longer distances (?).
While used scope loose nothing from looking through them, they take a beating from the gun they reside on before you buy them. Reticules get broken, lens elements loosen up, and the zeroing adjustments break. There is no free lunch with used scopes. They are a gamble as much as anything else in the used gun market place.
This is, of course, only my opinion based on my many years of shooting and your opinion may vary. For example, I have bought a 2x pistol scopes and found it unusable, and I have bought cheapy Red Dots and had them break, and I have several Ultra Dots that work very well indeed, and I have had scopes break from recoil.