Seems like most questions have been answered, but I thought I'd throw my two cents in as well. When it comes to scrubs, I would probably say online is the best if you think to order in advance but the bookstore isn't too bad if you're in a pinch. One warning about buying online, though, is that scrubs from different companies may not fit the same and you might get stuck with something you aren't completely comfortable in.
Numbers wise, I think two would be more than enough. I had two reserved for anatomy lab, but I really only used one. Yes, they'll be ready for the trash by the end of it all but getting dirty means you're actually learning and not just standing back watching other people learn. To the person who said they had a bad pair already, be very careful if you choose to wear those. While you're not expected to be in the best scrubs in the world, anything that is too bad is seen as disrespectful to the cadavers and you won't be allowed in the lab. Exercise some common sense and you'll be fine. I would also suggest having a pair of scrubs for any hospital time (ER, etc) you choose to do because your anatomy scrubs (even if washed) will likely be too dirty/smelly to wear on the wards. As mentioned, if you're doing anything with surgery they will provide you with greens.
For gloves, there are lots of places to get them (online, Walmart, most drug stores etc) but that first day the anatomy lab should have them available for you so no need to be too concerned.
When it comes to first day attire, I agree with what others have said excluding the "forever" part. You can definitely switch up your picture down the road if you really hate it by paying a $10 fee and getting a new ID made. It's a bit of a hassle, but it's better than hating your ID photo for 4 years!
I'm sure you're all nervous, but you'll see very quickly that there really isn't any reason to be and everything will run smoothly.
...oh, and allheart is a great site for medical gear. They're fast with delivery and normally pretty good with prices.
