I was thinking about buying a bmw 2003 530i in great condition but it has 250,000 miles and he wants to sell it for 2500 is that to much mileage and is that a good price?

Be aware that repairs on a BMW are really expensive. If the car is in really nice shape and you don't drive very much you might get a few years use out of it. Be prepared to dump it when major repairs come along as the car won't be worth the cost.

$2500 is better thrown away at the horse track-

Yes & no because you have to rebuild the engine soon. Sure you could baby it for awhiloe with extended life high mileage oil & get 10+,000 miles out of it depending how offen he changed & serviced it. But ultimately the rings & nearings are worn out & it will start smoking. And has low compression from worn out valve guides too. A 2003 with a new engine is only worth about $10,000 check the internet. So subtract $2500, could you have it all rebuit for $7500 or much less? $3-5000? Check around before you buy it. There is a few ways to do this, Have it disassembled & rebuilt by a BMW shop & re-installed, usually they give some sort of garantee, a plus. Or buy a reconditioned motor or just a short block *bottom half less cylinder head & have the original cylinder head rebuilt locally, & do the dissassembly, re-assembly & install it yourself. Or have the original engine rebuilt by a nachine shop using all new parts. Tou decide how to get it out, dissassemble re0assemble, & install, this is where mechanically inclined friends with tools & a garage come in. Rent an engine puller, Good luck.