Probably no money. Money and power in Anglo-Saxon England : the southern English kingdoms, by Rory Naismith takes into account all major coinage finds from early medieval England and begins in 757. If the Anglo-Saxon petty kings actually minted coins in 550, which I doubt, their use would have been incredibly limited.

It is quite difficult to provide a clear answer to this question due to the fact that during this period, money didn't have a value past its actual weight in gold/silver. One of the reasons for this was the fact that coin dies and mints weren't centrally regulated so they differed in size across counties and kingdoms. This also meant that other forms of payment apart from coins could be used such as ingots or 'hack silver' which would have been bits of silver cut from bracelets, coins and other types of jewellery.

As for the wealth of an average person, it would have been very little, especially considering that London was very sparsely populated at this time and would have depended heavily on 'peasant' agriculture.

Follow-up question: What would that amount of money buy? How many nights in an inn? how much ale, bread or meat?