Check out 5.11 and Danner. Expect to pay Between $120-180 depending on what you decide to go with. As you know, all boots will require a break-in period. My 5.11 and 1st Danners fit like a glove out of the box, my latest Danners took a week to get comfortable. Same goes with the issue boots, they'll take a while, but the 5.11 and Danners are still more comfortable.
Also, make sure to get some good hiking socks and liners. Expect to pay about $10 per pair of socks and $5 per liners. Gotta keep the moisture away from your feet. I just did a field exercise where a lot of people got blisters, and I usually do too, but I "invested" wisely and came through without even a hotspot.
As already said, don't bring your commercial boots to BCT. You'll have to wear the issued, so break in the ones you got and get used to them for the near term.
You'll be issued a lot of things prior to deployment. By all means buy what you want / need to make things easier for yourself (pouches, slings, holsters, cleaning supplies, flashlights, etc).