From what you have described, it seems like you’d need a new chain anyway.
Now, take a look at this video. This guy is replacing the chain, but not the sprockets.
Does this look like something you can do with friend’s assistance?
Certainly it is less work than changing sprockets (both front and rear) and the chain, but, you’d still need the stand and chain breaker / press and reveter, at least.
About the cost of the new chain, and chain & sprocket set
If you buy a complete kit, it’s around $250.
http://sprocketcenter.com/street-sprocket-applications/ducati/800-s2r-monster-2005-2008/sprocket-chain-kits.htmlIf you buy just chain, it’s $85.
http://www.monsterparts.com/pc/EKSRX/Chain-Sprocket/EKSRX.htmlWhen you are out of work, $165 feels like a big difference. I can understand your frustration.
Now, take a look at your bike’s sprockets. Than, look at the photos / video I posted above.
I hope there’s no missing teeth, and they don’t look like shark fin. (Because if they do, you have no option. Change everything at the same time.)
You “can” get by just changing the chain (that case, get the one I posted above from Jeff (Monsterparts), with screw on type master link. (He will do that with no extra charge.) That way, you don’t have to have special tool for riveting the master link. (BTW, I don’t recommend “clip-type” master link shown in the video at the top of this post.)
BUT, keep in mind that when you eventually change the sprockets, you will have to repeat pretty much the same work again.