First off, welcome to LRH.com! there's a lot of great info on this site, im sure you'll enjoy it.
As for the 223, i cannot give you any first hand experience since i dont have one nor have i ever shot one. What you've heard so far is all good, with a 1-9 twist barrel you won't be able to shoot the heavy bullets, this will limit your range, terminal performace, and your bullets will drift a TON once you get out there. I would look at a 243 win or other 6mm. 6mm's have great BC's and are cheaper to feed than 6.5s. I'm in highschool myself so i am also trying to save money while not sacrificing too much performance. You can always sell your 223 brass, that goes pretty fast if you post it in the For Sale section on here, snipers hide, 6mmbr, and others. A 243 will let you strech the distances a bit. If your new to long range shooting, a 243 will be more forgiving when shooting long distances. A small error shooting a 70gr .224dia bullet at 700yards will throw you WAY off, a 243 shooting 115 bergers or similar, is a bit more forgiving. Just make sure you get a fast enough twist to launch the heavies, there are also some good bullets in the 95-107gr range for the 243 if you can't find one with enough twist for the 115s.
As for your scope, i was pondering the exact same question a few months back. I settled on a Falcon Optics 4-14x44 FFP mildot scope. Have been real happy with it. It's clear and seems to be real good value, but it is a bit heavy. Costs just around 350bucks new. I can hook you up with a slightly used one (no visable wear) + burris Xtreme rings for 350 if you want. I rebuilt my gun and need a higher power scope for F-class. Nikon Buckmasters, Bushnell Elites, and Super Snipers are all good scopes and you'll be happy if you choose any of these. I'd recommend a variable power that has a low end magnification of no more than 6x, or it becomes really impractical if you have to shoot offhand or in an unconventional position.
One more small tip i have for you is, don't skimp on the bipod. Get a harris and be done with it. I tried being smart and bought a *** shooters ridge one at walmart, 3weeks and 40bucks later it was in the trash.
-Oliver