If you have storage room, its best to buy about 500-1000 bales at a time. Some companies will allow rental of their trailers so you can store the straw in there. They do not charge rental if you can empty the trailer out within 2 months i believe. Pine Straw Distributors in Raleigh should deliver to Charlotte, they have excellent straw, not sure of the price, but if you buy that many bales at a time you may can get it for about $2.90 a bale.
Don't know about del. Between trailer and truck I can get about 250 in 1 load so I have only picked up so far.
My wife saw a trailer behind a gas station in Huntersville that had them for $3.00 per. I will find out where and let you know. Where are you in Charlotte? If north, than exit 25 should not be to bad a drive.