[AstralTraveller (David)]

As rmcpb said, to see flares you need a H-alpha filter or specialist scope. Both are very expensive. To view surface detail you need a filter for the front of the scope as a minimum. Apparently the Baader solar film is considered the best and is the cheapest. I'm happy with it.

I'll also put in a plug for a solar continuum filter. It will sharpen up the detail on sunspots nicely, and colour the sun a pretty green (I like green ). With my 15cm achromat I can see plenty of detail in the spots (umbra and penumbra). You will also be able to see the spots change shape over a period of an hour or so, so it's quite dynamic.

All this assumes of course that we will ever see sunspots again in our lifetime.