What's your application?
I've bought magnets from amazon (the small itty-bitty 1/4" diameter x 1/8" thick or smaller), etc. I've bought from American Science & Surplus (
www.sciplus.com); I've bought from Penn State Ind. I've also disassembled disk drives to salvage the magnet for refrigerator magnets. My most "popular" source right now is used Philips Sonicare toothbrushes. A little surgery, and I have great sandpaper holders on my lathe. You have to do a bit of hunting on Amazon, but you can get good deals on a pack of button NdFe magnets with prime shipping.
Re: N number. Without getting into gruesome math, it's pretty immaterial for modern NdFe magnets. You'll get better pull strength by having an iron/steel cup wrapped around most of the magnet (so-called "back iron").
Don't use AlNiCo magnets (you may find them as surplus items) for applications to pull things together/pull things apart. They will *significantly* demagnetize.