As an economic historian of medieval Europe, I would strongly encourage you to take the economics of the period on its own terms. I find that sweeping economic histories are plagued by teleological approaches that oversimplify the period before 1500. Indeed, I can't tell you how many times I've read a book about modern economic history that makes conclusions about the medieval period and found errors that are verifiably false.

For banking Raymond de Roover can be a bit dated, but provides a good overview of medieval banking. He's also the main English language scholar on the subject. Check the bibliography in his wiki, http://en.wikipedia.org/wiki/Raymond_de_Roover

Robert Lopez's book on the commercial revolution stretches back to the Roman period is also dated, but presents the classic narrative. The core of the work can still be taken as true. http://www.worldcat.org/title/commercial-revolution-of-the-middle-ages-950-1350/oclc/186363&referer=brief_results

I love The Medieval Super Companies, which focuses on the Peruzzi company, but will also give you a overview on medieval economics. Much of the discussion is based on Roover, but there is greater stress placed on bulk commodities, which is the direction the field is taking. http://www.worldcat.org/title/medieval-super-companies-a-study-of-the-peruzzi-company-of-florence/oclc/29386865&referer=brief_results

Money and its Use in Medieval Europe will get you started on gold vs. silver currency in the Middle Ages and the relationship between the northern and southern shores of the Mediterranean.

For another specific study, Alan Stahl is the man on numismatics. His book on the mint of Venice would probably be a worthwhile read, considering Venice dominated large portions of the medieval trade. Furthermore, their currency was widely used throughout the Mediterranean http://www.worldcat.org/title/zecca-the-mint-of-venice-in-the-middle-ages/oclc/51481229&referer=brief_results.

I haven't read this one, but I love Steven Epstein's work, http://www.worldcat.org/title/economic-and-social-history-of-later-medieval-europe-1000-1500/oclc/297147067&referer=brief_results/.

I have more suggestions on a range of topics pertaining to medieval economic history if these aren't what you're looking for.

None of the following picks are likely to be uncontroversial, so I will let other commenters tell you why not to read them if they feel strongly about. (I happen to have bones to pick with all of them, but that doesn't mean they aren't helpful starting points.)

You could do worse than "The Wealth and Poverty of Nations" by David Landes, if you're interested for a global economic history that deals substantively with the question of Europe's comparative economic success over the last 500 years. If you wanted a counterpoint of sorts, Andre Gunder Frank's "Reorient" isn't bad.

Kenneth Pomeranz's The Great Divergence and Timur Kuran's The Long Divergence deal with China and the Middle East, respectively, in comparison with Europe.

If you want more of a textbook, Karl Gunnar Persson has a book for undergraduate economics majors called "An Economic History of Europe" that is quite straightforward and is quite direct in its use of economic reasoning.

Oh, and the claim about inflation strikes me as untrue - there were periods of both inflation and deflation over this period in the US. Friedman and Schwartz's "A Monetary History of the United States" has much more.

I'd recommend Karl Polanyi's "The Great Transformation" for you. It only covers through the 19th century, but it is thorough and brilliantly written.