I used an unloader brace for 2 years, and it helped tremendously. It was a prescription brace that cost about $1000 (with a compression sleeve), and my cost share was about $250. I tried drug store hinged braces first, and since they helped, I asked for a prescription for a longer brace. The brace stabilized my knee (I was bone on bone on inside of right knee-- needed partial knee replacement). My husband fussed that I was wearing it too much, so I quit for awhile, and I then wound up with a very painful foot (from the knee wobbling and the foot trying to compensate, as I was walking on the sides of my heel) and trying to get tendonitis in the opposite knee (from limping so much). I started wearing the brace again, and the other body parts started healing. This brace had adjustable sides, so I could jack up the inside of the knee and take the pressure off of that side. The brace made enough of a difference that I was climbing around inside my company van, and someone commented that I didn't look like I needed a knee replacement (1 week prior to PKR), since it made me much more mobile. I even wore the brace when bicycling around on vacation. In this situation (waiting for a PKR), I would absolutely recommend an unloader brace.
I am back in an unloader brace for the other knee, and it helps somewhat, although less than it did with the other knee. This knee has more damage, so the brace helps me walk a bit longer before the serious pain sets in. Since I now knew what type of brace to buy, I purchased one off of ebay that looks like my old brace and was made by the same company. Total cost was about $35 (much better than my cost share of $250 for the other brace)-- and this "used" brace looked absolutely new, like someone tried it and disliked it. I used the company's website to determine what size to get. By using the brace and a cane, I am able to walk more steps before the serious pain sets in. It does not help me as much as the other leg's brace did, as the knee damage is different. I have more trouble with anything touching the sides of the knee this time. I wear the brace daily as it does help.
The tech who fitted the first (prescription) brace said I was to wear it under my pants, using the compression sleeve. However, since the brace slid downward and needed adjusting every few hours, I wore it outside my pants. This worked fine, and I just tugged it up when it slid down. I didn't wear the compression sleeve much, as it was hard to get on.
My recommendation is to find a brace on ebay (buy one labeled RA brace, for rheumatoid arthritis) and try it. It is a cheap way to try a brace to see if it gives you any relief. I have 2 Townsend braces (one left leg brace from ebay and one prescription right leg brace) and a Don Joy brace (from ebay). I am so used to getting quickly in and out of the Townsend ones that I have trouble getting used to the Don Joy one. Use the brace company's website to determine how to measure for the correct size. By carefully watching, you can get a good brace for under $50 on ebay.
Good luck.