Hello Kuni,
wellcome, I thought id just add my 2 cents. I bought My NSR250R about 4 months ago. I didnt look for a mint example just one thats been mechanicaly looked after. I paid £1200 for my R it just had a new crank and i belive looking through the history the top end was done as well about 3000kms before the crank. so the bike was ideal for me.
Now im a big fan of bikes any bikes i love em, BUT the nsr is fantastic even stock suspension (and mine is 15 years old now) it out handles bigger bikes. At the last track day i couldnt stop laughing as during a long corner i was changing up gears and catching bigger bikes and in some casese passing them. ITS FAB. As for a money pit well thats up to you. You can keep it standard and just keep it maintained it shouldnt cost much, Parts are fairly easy to get and LIKE everyone says its a honda.
For me ive already spent £600 on parts from tyga, another £40 on brake lines £150 on new rearsets, £140 on a ZXR400 front end and im goning to have to spend another £3-400 on setting it up when the bits arrive from Tyga. After that i have planned new bodywork, ohlins rear shock etc etc etc it goes on. but its what i enjoy and it makes me happy
Stay tunned to this site, Lots of clever people here. its helped me no end.
I think i can add, make sure the bike your looking at has been well looked after, you dont want a rebuild bill before you get to ride it.
Cheers