Look at/for a "good" brand 2x72" machine. Bader, KMG, Burr-King, or any other brand that's been around for a while. Steer clear of the johnny come lately ones..... they will be there today to take your money, but likely gone tomorrow... when you need service/parts/help.
Expect to pay $1,500-$3,000 for a quality grinder. And as Ken said..... spend the money and get a variable speed!! You might not know much about right now, but once you use it, it will amaze you.
Belts: Two things..... buy premium belts, and steer clear of cheap ones..... you'll use twice as many cheap belts as you will the premium belts.
Everybody has their favorite brands and progression of grit sizes.
Personally, as a Bladesmith, I start most of the shaping at the forge. I use a 50 grit ceramic belt for my heavy grit, but also use 120, 220, 400, 600, and 1200 grits. I also have some specialty belts such as cork/abrasive belts, Scothbrite finishing belts, and some belts that are called "open grit" belts.