hop on the ninja250.com board and see if anyone's selling one there.
muzzy is good- i have a muzzy i bought used for $150 and it's awesome. i would go full exhaust (it won't cost you much more) and just skip the slip ons.
i think you should check bikebandit.com and chapparal.com, personally. wheni was watching ebay for mine, the prices for used weren't that much less than new. i was about to order one new, but the cheap one came up locally, so i went for it.
also, if you have any local used parts / salvage shops, check there. 250's come up crashed alot.
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