Hi, Sarge,
Entire books have been written on Lugers (note spelling; Lugar is a Senator from Indiana), so it is not easy to say from a brief description if the price is good or not. Obvious things to look at are the percent of original finish, whether numbers match, amount of rust or pitting if any, and the overall wear. There are few 1918 pistols with good bores or with high percentages of original finish, so it is possible that the one you saw is reblued and/or rebarrelled.
Nevertheless, that is not a bad price (by standards in this area) so it might be worth going for anyhow if the gun appears to be tight and not obviously buffed to heck and back.
Jim