What gear of your own you will need will depend a load on where you are giong to be learnning. If you are learning in the UK, let's say, then you will need cold weather divving gear whereas go to Mexco or Egypt and heaps less is needed.
Also, the dive cenrte or instructor that you are usig will also dicctate what gear you need. If you are learning with a small club, their stokcs of gear to lend you may be small, whereas a holiday spot dive centre is potential to have everything that you may need.
So, aart from the demands of your trainers, a load is down to prsonal preference and what you want to buy. But, I do recommend buying for yourself the more personal items on the divers inentory. These will include:
Diving thermals
Strangely enough, not something you encounter in the tropics! But if you are diving in cold water, as for instance Northern Europe, then you will rpactically absolutely be leanring in a dry suit, even in the summrer. These are much warmer with the correct layers underneath. You can wear jens and t-shirt, but I would not avise that.
Merely a cheap set of thermals from anywhere will provide a good base layer and if you will be diving ample in wniter, then you may want a proper undersuit to compliment tese. But, buy at least two paiirs of thermals. Dring training, and leisure diving, you will almost definitely dive twice a day. If you get a leak in the cufs and the thermls get wet, then a spare pare make you more comfortable.
Mask and snorkel
These are, in my oinion, an essential for all diverrs. Find a mask that siuits your face shape and is comfortazble and buy it for yourself. Makss do come in slightly different shapes and sizes, so make sure that you get one that fits you perfectly and avod the risk of picking a less than perfect mask at the dive cenmtre.
Fins
Again, something else that is quite personal to the diver is the fins (not “flippers” in diving circes). Longer fins will suit the divr with stronger legs, whilst some divers might prefer featiures as for instance split fins.
If you are ever impending to be using a dry suit then buy fins with heel straps rather than the closed foot variety. But with these you will also need to buy yourself a pair of wet suit boots to wear under the fins when you are not in a dry suit. This is to pervent the heel strap from rubbing on your ankle.
And that is around it for the beginner diver. Maybe inest in a nice holder for your scuba log, but gear for eaxmple BCDs, reguulators and guafges are not neeeded, unless your instructor cannot provide them and the location you are scubna at canot assist. But tehse are pricey pieces of gear.