Depending on how you are set up you might want to look at computer storage and backup - you'll be amazed how fast you can fill up disks
That is a very worthy topic, and oft forgot, but probably should come before any of the other camera-guff you can get.
Thing is, the start-point, isn't so much getting hardware, but sorting ideas; you need a strategy for archiving, really before you want the hard-drives, and again, oh-so-much depends on what you do, and what you do with it.
Good tip for a newbie here, starting out, is to buy a portable pocket drive; they start from under £50, and you dont need a huge one, 500Mb is probably more than enough to be getting on with.
Trouble with 'In-Computer' storage is it's in the computer, and if the HDD goes bump, so do your piccies.
On-Line storage? Well, there's a lot of host-sites, but they make your pictures public; and there's subscription 'cloud' services, but you have to keep paying for them... a pocket drive you only need pay for once!
As a basic methodology; after each outing, clear the camera cards down to the computer, and immediately back them up to the pocket drive. IF you keep 'old' photo's on the camera card, you can easily get in a right muddle, with what's what, so clear them down for next outing, it saves fafffing trying to delete shots from the card on the camera when you run out of card-space.
Then, with two 'sets' of picture-files; one on your computer, one on your pocket drive; you can diddle away to your hearts desire with what's on the 'puter; messing with sliders, changing colour balence, cropping and sizing, and making something to upload to boto-phucket or farce-broke, or wherever... you have the 'masters' on the pocket drive if you eff-up and make one 60pixels square instead of 600px or something
But then.... you create a new file on the pocket drive; you have one for your 'Master' images, straight out of camera; but, the second is the 'Display' archive for whatever you make from the originals; which, in my case are the final edits, in the full-size form, before I resize them down for web-upload... cos that the easy bit! And means that you dont have to re-do all the edits if you loose the uploads or the computer goes bumpo, or whatever.
Keep the Pocket drive DISCONNECTED from the puter, when you are NOT transferring files to or from it, and try to do that as seldom as possible; if not connected, cant get infected or wiped by anything on the computer, can it?
Then, when you have experimented and played and worked out what you do most, and how much you are likely to shoot; then you can revisit the strategy, and other hard-ware may be more suitable, and more refined archive solutions pertinent;
BUT, pocket-Drives are pretty cheap, SD Card cheap for maybe 30x the 'space'; and you can keep them safe on a shelf not on the computer; and even 'off-site' if that's a worry.
It's a place to start.
BUT... top tip, is to KEEP that Hard-Drive 'dedicated' to your photo's....
Daughter was a bugger for this' she'd go round her mates, and pick up whatever flash drive or porta-drive was to hand, and end up with a mix of movies and pop-music and photo's and all sorts... then come crying that she'd 'lost' her home-work.... no... you DIDN'T loose it dear... you ERASED it! When you formatted that flash-drive you 'thought' only had "Glee-Club-Movies" on..... No... sorry, your BROTHER, didn't wipe your home-work either! I know... you loaned him the chip to watch Glee-Club-Movies on..... and told him to 'wipe' it when he'd seen it... he did EXACTLY what you told him to! He wiped the whole card... Lol!
Keep it to your-self; keep it dedicated to photo's, and save potential calamities and confoundements!