you need to buy an event item for the DA shop, its at 2000 dp; its one use only to host a tournament
and if you want to give dp prizes it should be from your own dp; so basically you need to spend a lot of dp to host a tournament for ppl to enjoy and thats why not many ppl host tournaments here expect for the staff
Just to add something: Sometimes myself (or any other staffer) feels interested in sponsoring a tournament hosted by someone who had purchased the Event Host Item from our Central Shop; however, that is only if we're convinced that the tournament idea is something cool. It really depends and situational.