really the major costs are associated with dealer service... and of course ducati oem parts if you need replacements. but that's the same with any make. fortunately there are a good number of aftermarket vendors out there that can easily replace most consumables (chains, sprockets, brake pads, rotors, clutch packs) for about half ducati oem. there's also a lot of classifieds that can help out on used parts... here, the ducati index, and sometimes ebay.
some ducati aftermarket parts are more expensive than that found for the big four but that's probably due to the lower volume of ducati's out there. exhaust slip-ons would be an example.
if you do a lot of the maintenance yourself you can really cut the impact to your wallet. not accounting for my time my last 2valve 12k service interval cost me about $76 for new belts... my last 2valve 6k service interval cost me about $12 for two closer shims and $5 for a valve guide seal. of course i've spent some cash on the tools both standard (liquid gasket, thread locker, anti-sieze, metric wrenches, sockets, allans, bike stands, etc.) and ducati specific (engine turning tool, haynes manuals, valve video). but i'm a nuckle dragging tin bender at heart so tools are as cool to me as the bike. there's not a whole lot of ducati specific tools though, and many you can make yourself. not inlcuding taxes or unusual circumstances dealer 12k service will usually be in the $400-$550 range, and the dealer 6k service will be in the $250-$400 range. add about another $150-$200 if you own a four valver.
oil changes are cheap and easy... oem filters can usually be bought in bulk of 12 for about $8-$9 each... oil is what you want to spend on it (for me it's about two cases of mobil 1 every three oil changes which comes to $50). it breaks down to $25-$30 every 3000 miles for me. the dealer 600mile service (basically amounts to an oil change at "most" dealerships) will run $200-$250.
i've never really got to experience the good fortune of being near a "good" dealer... in fact the dealers i've had experiences with have cause me to do my own service because you just pay them to screw your bike up. i can do that on my own thank you.
i'm finally going to shell out money for a nice bead breaker for mounting tires, i got sick of chipped paint or dinged rims from shops... between that and the static balancer i'll spend about $300 on tools, but with two bikes that i have (and hopefully a third soon) at $30 a hand carried wheel to mount and balance or saving $150 per tire purchase it'll pay for itself soon enough.
i like doing my own maintenance though; it allows me that zen time to relax and wrench. it also provides me with the independence i like. to others it's a bother so they like paying someone else to do it. you don't have to be rich to ride a ducati (although i'm sure it helps) just motivated. bikes cost money... there's no way around it.