SpotGoblin

This is the way. Especially if you're willing to trawl through places or online listings looking for half-crowns, sixpences or threepences. Crowns are usually inflated and are sought for numismatic value. The smaller the denomination more usually closer to spot it will be (for the older British coins.) You can even find the occasional pre-1920 at times. In terms of other coins its sort of a pot luck, you have to be willing to look through odd stuff; for example some world commemorative silver coins can be found near spot. Its fun as a side/hobby thing to locate and find these but they aren't exactly plentiful options. If you want less aggravation and despise paying over the perceived odds then I heartily agree with the other comments buy gold sovereigns.