Always take extra cash with you, they may have other bargainous stuff around that they will part with.
not old bike parts so you can tune out if you want i won some ford mexico steel wheels for a bargain price of £20 . went to pick up and the guy had a large garage with a nice capri in it . i spot a 7.1/2" rs 4 spoke wheel on the floor . which are very desireable and very hard to get hold of . a set of 4 will easily fetch £700 . it has a flat spot and a bit of kerb damage but nothing spit and polish couldnt sort out . he had been using it as a way to store his hose pipe . i tentatively offer £20 . its now sat under the table . trip well worth it