That used to be my strategy until a salesman knocked on my door offering heavily discounted ceiling insulation, which is something I had half-heartedly always wanted but never got round to buying. He said my address was one chosen by the government to give a subsidy to but funds were limited so it was first come first served or risk missing out. Sounded suspicious so I checked with the government who confirmed everything the salesman said was true. I got a 2nd quote from another installer but the door-knocker was cheaper so I bought his. I wouldn't have known the subsidy was available without him and would have missed out on a genuine rare high-value giveaway.