The .300 is one of those rounds that are worth pursuing because it comes in some nice rifles, but otherwise is out-classed by the competition.
The 99s were simply too expensive to make, and there are literally millions of used ones out there to fill the demand that exists. Brownings chambered for various good cartridges and .308 Marlins are also available for levergun fans who want more power than the .30/30 packs.
Personally, if I were looking for a non-bolt woods gun, I'd probably pick up a decent used Remmy Model Six or 7600, with the straight-comb stock if possible. See 'em pretty often for $350-$475.
