The Doctor reflex won't fit the 100-200 dollar budget. In fact the only sights that will fall in this price range are the cheap Barksa reflex or one of it's "knockoffs", it seems that this particular 4 reticle reflex is available in a vast multitude of brands. I tried one in the Sightmark branding and it would only hold zero on my 22 caliber 617.
I would suggest that you up your budget to the point where you can purchase a quality sight that really can hold zero on a gun with some recoil. Take a look at the following web site for the J Point Reflex. While it's double your budget and shipping to "down under" will only add to that cost, IMO you won't find a finer way to mount a reflex on a revolver and I can fully endorse this sight. BTW, note that JP Rifles offers a Doctor to J Point mounting adapter, so if you can find the Doctor locally you could use this mount with the adapter to mount a locally purchased Doctor reflex.
JP Rifles
Now about the J Point reflex, as you can see in this image I'm a real fan of this sight. Those 3 sights were an expensive outlay but I spent the money because of the advantages they provide, which are light weight, ease of holster mods, and a LOW offset from the bore axis.
However, it's NOT perfect, it's very slightly compromized by design choices that were made in order to improve it's durability and usefulness on a wide vareiety of firearms by people who actually SHOOT guns, not Lab Geeks looking to produce a sight with the sharpest reticle. In plain terms, the dot is a bit fuzzy and it has an acrylic lens instead of glass. However, it does what it's supposed to and holds up well in hard use. In addition it's the only reflex sight I've seen that has a sight notch molded in the case, which can make it much easier to find the dot because you can co-witness with the front sight until you pick up the dot in the window. If you have tall enough front sight installed and fitted, you could also also shoot full co-witness using the notch in the event of a battery failure. Following is a link to my range report for the J Point with more pics and some notes on installation so make sure to read all of my posts in this thread.
Purchased 2 more J Point Reflex sights, range report.
PS; note the rubber grips, they are there because I actually shoot my guns a lot and the J Point hasn't lost zero on any of them. However, as I found recently with the 620, a 158 gn. +P 38 shoots a LOT higher at 25 yds. than a 130 gn. std 38. Anytime you change your loading, you will have to make sure to have the tools to reset the zero. One of these days I hope that JP rifles produces a J Point with a vertically graduated reticle instead of just a dot.