I am not sure what reasonable cost is, but a great value is the S&W 1911 series - they work and can compete with factory/custom makers of the same quality costing 3 to 4 times as much. Personally I think Kimbers are a great deal also but all of mine are old. I hope they are still as good.
Springfield Armory, Mil-Spec 1911s are a bargin at somewhere in the $500 range (would rather have one of these than a "bargain" on a lesser made gun at $300).
A real bargain, in not quite as nice a platform, are the used Star pistol models: BM, B, A and PDs Usually less than $250 though PDs run in the $350 range and are not quite as durable.
You might run into a used S&W single stack DA/SA or DAO auto in 9mm, .40, 10mm or .45 for anywhere from $350 to $450 (saw several of the 4506 and 645s at the last big show for that price).
Sounds like you want an auto (note how a trained investigator concluded that from the "magazine" clue
) but if revolvers were to be considered the old K-frames are quite useable as carry guns, especially the fixed sighted 3" models like the M13 or M64 and M65. Those are runnin in the $250 range quite often though they are going up. I would certainly rather have a S&W revolver than an off brand auto for the same money but that may be just me.
Non of the above is a recomendation, just a report. Personal defense is far to important to just take other peoples advice...it is a life long study: If you don't study you wont live as long :-/
Good luck!
Jim