To get thru class you'll need mask/fins/boots/snorkel - unless they're providing that. I suggest trying/buying a mask locally or at your destination - that's the one thing you want to fit
well during your class so you can focus on drills and not clearing it constantly. If you buy all 4 instead plan to spend $100-300 for good basic dive gear.
Is Alabaster anywhere near any of these locations? - Divers Supply has a good reputation and decent prices.
Retail Locations
After that if you continue, most people will eventually buy regulators, a BCD, and often a dive computer. Decent gear in a package starts around $1000 total. Here's an acceptable example of that:
Aqua Lung Pro HD Essential Package - Packages & Combos - Scuba Gear I have what would be considered upper end in 2/3 categories so I'm into about $2800. A more technically focused computer can be 1/2 that by itself but there's also decent models for $200. Mine cost me $300 about 6 years ago.
Some sort of exposure protection also - if you wind up later diving in the Gulf of Mexico not much is needed but you should have a minimal wetsuit since even in warm water your core temperature lowers over multiple dives. Also if you plan to dive the rigs (you should when you have more experience) they're metal, rusty and sharp so having some neoprene in between isn't a bad idea. Coral is razor sharp also...lol. Full wetsuits run from $2-500 depending on features/thickness.
Add several hundred for all the things I've overlooked...Add another $5K if you get serious about u/w photography...lol. I have $3500 in video gear and don't own lights yet.
Another concern since you're starting your diving in the Red Sea is to look for internationally serviceable brands. Those are often the ones that have been around a while also - Aqualung, Scubapro, Mares, Oceanic, Cressi all make that list. They'll have extensive coverage around the globe - and as important - access to service parts.
have fun with your new addiction...