A fair price as compared to what?  There are a lot of shops that install sleeves.  There are thin walled sleeves that are cheap and thick walled sleeves that cost about $50.00 to $75.00 more than the thin walled sleeves.  There are shops that take the time to do the job right and there are shops that rush through the job to try to compete with shops that advertise their services on Ebay.  It cost more to install a thick walled sleeve because of the additional time it takes to machine out ALL of the original iron sleeve and the additional time it takes to match the ports on a thick walled sleeve.  You can spend anywhere between $150 to $350 for the sleeve and the labor.     

Find a shop that has the proper equipment for the job and machinist that will do the job right

You definitely want to spend a bit more on a good builder.  I've seen sleeves slightly rotated in the bore and not chamfered to the ports.

 

I'm just wondering if I'm better off buying a different cylinder.

Yes, if you can find a good clean cylinder for under $200 it will probably cost you less than getting your current one sleeved.  I may be off with the my $200 but that will depend on who you take it to.

If you want to repair the one you have then Jerry is right take it to a shop that does a good job and uses a thick sleeve.  If you are considering sleeving your current one, if you welded on it you probably need to check for warpage and depending on where the weld is you need to consider if the heat affected zone will make it brittle and more prone to cracking again in the future.   

Having said that I've seen some pretty goobered up cylinders run pretty hard as long as the decks are flat and the cylinder is not out of round.

I have a cylinder with a new cool head, and has a fresh sleeve job.  I believe I even have the piston, wrist pin & bearings, the billet thrust washer too!  If you're interested pm me what you had in mind.  It's somewhere in my closet collecting dust. LOL I know I paid $450 for the cycling alone.  But I knew I was getting a quality job.  If I was you, I'd have Carl aka ICERACER, reinforce the cylinder, and really, I'd just send it all to him.  He's got the knowledge and means to do ALOT of things to make the 250 exactly what your looking for. 

One of these days I'm going to drop off my whole 250 and have him go through it.  I've done most of what I'm mechanically able to do, now it's time for a real professional to finish the quad.  My wife's going to graduate college in the next year or so, and she wants to walk across the stage.  Somewhere in w. Virginia...maybe that would be a good time to do so.