I'm looking for a good price on a bunch of electrical supplies, like 1000 ft of 0/2 cable, master breaker box etc. Anyone have any recommendation who has good prices?

hamilton electric might.  other than that, grainger might have what you're looking for.

Grainger is a place of last resort for me, prices are way too high, like double retail..

Not sure the electrical supply places will be much or any cheaper than Home Depot or Lowes.  The lower pricing they offer is usually to bigger/regular accounts, not a one time customer.  Company I work for has an account with Graybar, but I'm sure we pay more for our stuff than others simply because we don't place large orders with them.  I once tried a plumbing supply house thinking I would get  a better deal and I'm pretty sure the guy just made up the price off the top of his head after I told him I was paying cash for the part I needed.  Plumber who has an account there said I got ripped off.  Probably best to call around for the best overall price, I"m sure like most things one may be cheaper on one item and more expensive on another.

I have visited several electrical distributors over the years when I needed a specific part that Home Depot or Lowe's didn't have.  For anything standard like wire or normal outlets, they are always way over Home Depot or Lowe's.  

Here is a great way to save more at Home Depot or Lowe's.....Go to Ebay and you can buy the Lowe's 10% movers coupons for about a dollar.  HD will take them as well.  Since I can't go into either place without spending at least $100, I always come out way ahead.

Elliot Electrical Supply

Graybar

Rexel/Summers

City Electrical Supply

C.E.D.

Dealers

Hill Country supply

Call around and get quotes, they will try to compete with eachother right now because things are slow right now.