I suggest aiming for the universal gears for starters.
Kahos
Celeb Rings
GTB / Toad Shields
Immune / Deviling Mufflers or Manteaus
DL Sleips (If you can't afford, go for DL boots)
etc
Once you've got those, you've got gears you'll use on basically all of your characters. Of course, to be very efficent you'll need a GR armor, as well as a marc armor so you don't get frozen. But you should first and foremost go for the GR. As for your budget on a weapon, if you tell me how much you're willing to spend, I could probably tell you what you could get with that. But, the best for a knight is DDT or DTT nib, hands down. Second best... I'm not too sure, this also depends on how often you'll be getting endows, if you feel like making an endowslave or not, etc... But remember, you should always have a one handed weapon. Shields are made hax in this server, and you honestly should not go without one as a Knight.. However, the choice is yours. Whatever weapon you do pick though, you'll mostly likely use one or two doppels, one or two turtle generals, one phree, etc. You may go crit, and in that case, you'd save a lot of money from buying celebs as you could buy crit rings instead. Don't worry about a PCB until later, and for your mid-headgear.. You'll need quite a few as a knight. On my knight, I carry nightmare ears (so i don't fall asleep), DI ears (for the cast reduction bonus with my sleips and the hp bonus), ESL ears (so I don't get cursed), etc... All that junk.