The two biggest sources of salvage sales are Copart.Com and Insurance Auto Auction, mostly known as I.A.A. Most Insurance companies have a contract with either one or both of these companies. Value paid to owner is mostly determined by CCC market research or similar and the salvage value, or min bid is usually generated by the Auction company based on averages. You can buy from any salvage sale they will help get it delivered to you.
You can get some good buys on older obscure stuff but not so much on newer High End models. I had a office at Tampa (Riverview) auction for a few years, not many bargins from there for sure. Florida sales of stuff with a good title are VERY high and even the salvage title stuff, which is most of the bikes being sold, is astronomical as well.
Good luck and DO NOT TAKE what you see in the photos as gospel. Although you can only bid online, you can inspect, if your a registered buyer and you should NEVER buy a bike without a inspection.
Comment above about Ins Damage Appraisers not being motorcycle knowledgeable, sorry to say, is true and a lot of damage is overlooked and misrepresented on the auction site. The adjustor will request a value once he thinks visually the bike is a total, then he will write big ticket items like tank, exhaust, fairings etc that have easily obtainable prices upto the total loss threshold then stop his appraisal and settle with owner and send bike to auction, Auction will then take adjustor supplied info and represent damage as that. Which most times is maybe half the real damage.