I think the community is fairly misguided here. There’s definitely a jump, but there’s no reason the next step is buy everything or even buy all deluxe sets, usually a second core, C&C and 2-3 targeted data packs is all you need to get serious GNK/SC decks. Total you’re looking at ~$100 additional investment on top of your first core set. We had a new player join our meta recently. We recommended he pick up C&C, Sovereign Sight, and Breaker Bay along with a second core set. From that smaller investment there’s a decently strong Hayley and ASA list that can be played (note the ASA has a few additional cards since the player bought some packs before consulting us lol).
Then once you get bored with those decks all you need to pick up is a faction box and another 1-2 packs to build a different runner/corp deck. For example you may branch into H&P next and then buy Blood & Water for Jinteki (Obakata, Miraju, SFT) and for Crim Quorum gives you PIOT and Taps along with several strong Corp cards. Alternatively you buy TD and Crimson Dust (PriCon, Breached Dome, MCAAP, Aumakua) to go Crim/Weyland.
NBN’s a bit trickier as you probably want HHN + something else right now, but you can probably make a solid sync kill, or EdTech deck with D&D + Down the White Nile (NGO, SSL, EconWarefare, Jua, Jinja), 23 Seconds (HHN, CtM), and then a 3rd pack based on which of the above you want to play EdTech is obviously council (Degree Mill, ID, Death and Taxes) or Escalation for Sync (Boom, Scarcity, FC3, D2D).
If you took the above 3 purchase points you’re looking at $80 for 2x Core, $60 for HB/Shaper, $60-70 for Crim/Jinteki or Crim/Weyland, and $60-75 for NBN. At this point you’ve spent $260-285 MSRP and have at least 1 solid deck for 6/7 main factions. That’s less than half the cost of the entire set and it makes some super viable decks. Assuming the player is interested after the first jump they’re also probably picking up the new packs as they release which gives even more options.
TLDR: It’s pretty easy to buy into the game slowly in $70-100 increments after the core set. We just don’t do a good job as a community of helping new players.A good diverse & competitive collection can be built for under $300 including the initial core purchase.