I lived in Augsburg which is 1/2 hour away and didn't really bother with the coin shops, there are quite a few. The easiest way to find the shops is to buy one of the many coin magazines and then find the shops. There is one coin shop right by the main railway station (Bahnhof) which you would probably walk past if you come out of the east side (I think) and it has a lot of coins on display in the window.
There's plenty of stuff within Munich and even more around. Bavaria is just full of stuff. You can use the BayernTicket after 9am (i think) for cheap travel on non-ICE trains to go to Salzburg, Nuremburg etc. Within Munich the best places are probably by the cathedral and Rathaus (and you can go into the bookshop opposite for a but of an aerial view. There English Garden is nice (and apparently if its hot lots of nudists out though I never saw them) with its pagoda.