Hi ScubaRookie
You've been given a lot of good advice so far and I'd like to add/repeat a few points.
*You will need and want your basic gear for class. As you intend get it locally, it must fit and you are not prepared to sort this out online. Mask, snorkel, booties and fins. Devour the gear forum and lean about differences before you get to the store. Wet/Dry snorkels, Purge/no purge masks, are corrective lenses part of your need? Get the idea, lots of details even in the basics. Expect to spend $150 - $300 depending on needs and preferences.
*Great lakes check-out dives, 7mm wetsuit minimum. A core warmer is probably also in order. Many choices there again devour the exposure protection forum. Drive a stake in the sand and buy the protection you need to dive at home so you can become a safe and proficent local diver.
*I'll defer to more seasoned travelers about what you need for your trip. But a 3mm suit is a minor expense and you may even enjoy it for a few shalow water fresh water dives in the summer. It's a fun break from the heavy rubber.
Regulator set and BC. Best not to buy until you are certified. Believe it or not folks do get certified and never dive again. Meanwhile in class ond on cert dives pay attenton what you are usuing. Devour the BC forum and decide what you want and shop/try from there.
If you can't spring for the Regulator set and BC together get the BC. It's the heart and soul of your diving. Everything about your buoyancy control and how you function in the water is built around this item. As a novice diver any rental regulator will serve you well. Expect $400-500 for a BC and $500-$600. for a complete regulator set (Ist stage primary and alternate second stages and full analog instrumentation - tank pressure, depth, compass) You can go alittle higher or lower than these ranges but I think that money will get you into a good selection. Remember to get a cold water regulator, this is true even if you do not plan something like ice diving. At moderate depths you will encounter water cold enough to challenge a warm water regulator due to the cooling effect of delivering compressed air to you. We dive Sherwood Blizzards (we are in Maine) reasonable cost, highly regarded in cold water, easilly serviced almost anyplace, and wicked reliable. A cold water unit will be dandy in warm water.
Computer.. I usally discourage new divers from jumping into this accesory but if you intend to dive a lot on the trip you will want one in time to understand it before the trip. Ge a nitrox capable unit for future growth, it will also manage plain air dives. $300 - $500 as a range. IMO save your money and skip air integrated, let alone wireless. As a minimum you will need a timepiece, something as simple as a cheap wrist watch with adequate depth rating will suffice.
Take your time, asking questions is a great beginning. The New diver, Basic and gear forums are a tremendous resource. Find a model you are interested in? Do a search, you are probably not the first to mention it. Becoming gear savy is a bigger challenge in many ways than actually getting certified. This is real money, your money, take your time do your homework and welcome to the sport.
Pete
If he's ONLY going to dive the Great Lakes for his OW cert dives, he can rent a regulator, which he'll probably do anyway. He needs to be aware of the potential for LDS over-hype on "life support" equipment. Of course, we all know that the best regulator is the one sold your local dive shop. 
