New rider here, vistavette is 100% on point! I just passed my MSF about two-ish weeks ago. If you're taking the MSF Basic RiderCourse, they provide the bikes and the helmets, you just follow whatever policy they have for dress code. Mine was long sleeves, over ankle shoes, sturdy pants (like jeans), and gloves (any kind of full gloves, really). If it's going to be hot outside, bring a cooler filled with ice and water, you'll need it.
The bikes they have on hand will usually range form Yamaha TW200s to Honda Rebel 250s, to Honda Nighthawks.
I bought a Buell Blast some days before the course, then a Honda Rebel 250 after the course. I don't what it was about the Rebel I had for the course, but I had fallen in love with that bike and had to get my own. I'm finding the 500cc single in the Buell to be a great starter bike. It has a lot of torque and can go more than fast enough to get you in trouble. Meanwhile, the Rebel seems to be a great work commuter seemingly borrowing from the "slow car fast" principle.