Second hand Glock 27 in a 40 SW. Comes with three magazines. All 8-round capacity. $400??
That's a fair price. CDNN is selling NIB G19's for $500 (no shipping charges and no sales tax).
BTW, those should be 9 round mags, giving you 10 round capacity with 1 in the chamber.
My G27 (I've had it since about 1990) is the one that gets shot the least. Compared to the G19 (and the G23), it has "snappy" recoil that results in slower follow-up shots. But it's a very reliable weapon.