I'm looking for 1948: Five-year plan Mining and oil Scottnr:1280#1283 Michelnr: 1268#1271 Mint or used, but if used, in very good condition, without anything on the backside (I want a scan of the backside as well). In return I can send a good suprise packet of soviet-union, I also have some double Liberia, or other things as well.)
BidStart has a store with a set of MINT... here is the link... http://stampwants-stamps.bidstart.com/Russia-1280-1283-Mint-NH-Scott-210-00-/49578712/a.html
I think I spend my money on a nice dinner, in that case. That is quite expensive. 3x as high as the Michel cataloque worth for this set (mint). I'm looking further for a used set with spotless backside then.
The link you sent has the catalogue price; Regency Stamps is an auction house. You can make an account on that site and bid on the set. I bid on other sites and have seen Regency before but never bid on it so I don't know the 'trend' (30% of book, sniping at the end of the time period, etc). On some sites, many of the same people frequent the sites time after time and after you start bidding with them (everyone has an account name that you can see) you will come to know their habits. I for example go in with a bid at a certain percentage of 'book' value as a 'stop': I get an email if someone overbids me and then I can go back and take another look... do I REALLY want this particular item? I also belong to the APS and look at comparison offerings to see where the 'range' of values lie before bidding.
One other comment: on the BidStart site, there is a Contact button on each offering, allowing you to communicate with the Seller. You can always go in after your research and make a best offer; some items have a "Best Offer" button. I have gone in with as low as 70% (80% is usually more taken) bid on their cost and I have only been refused just a couple of times... most folks just want to get rid of inventory and usually list with a little 'fluff' in their price.