2004 was a transition year and the Sportster was offered in an LE model with a 135 HP 2 stroke or with a 150 HP 4 stroke. For a 2 stroke model in very good condition I would say $5000 is the right ball park for prime summer prices, this depends on the accessories options, etc. For the Sportster 200 4 stroke this would be a very good price.
I just bought a 99 Sportster 1800 twin engine (170 HP) that needed an engine to be replaced and other work, looks good from 20 feet away, less good from 5 feet away for $2,200 and found a good used engine nearby for under $500. With luck I will have it out on the water for the first time this weekend (I am replacing the wear rings on the jet pumps today and putting fresh pump oil in them). Total spent on it to date is getting close to $4,000 which is a bit over what I budgeted, but $450 of that is going into the trailer alone (new LED lights, all new wiring, new fenders, 2 new tires, old ones were starting to dry rot and a new wheel hub on one side). Add a cover, some new hydro turf, and some new upholstry and I will likely be in the $5,000 ball park, but all that will be done as I go along, not as one big expense.
Ike