So I have decided I want to start a Daemonkin army. I have a few things for general Chaos already and want to figure out what my next purchase(s) should be since I need to make a shopping list of sorts. First, I do like the fluff and aesthetics of actual Chaos Marines so I want to go for a real mixed warband approach, with some daemons and some Chaos guys (not just daemons with Gorepack like you often see). I also really like the big monsters, Maulerfiends and Soul Grinders especially and I also really like the Daemon Prince model and Helbrutes aren't bad either. In the end though I want a casual, fun and fluffy army that really drives home the mixed warband of renegade marines and hellspawned daemons aspect.
What I currently have is pretty limited, but it's:
* 1x squad of 8 Berserkers, assembled to have 2x Chainaxes, 2x Plasma Pistols and a Champion with Power Axe (one of the
DV chosen models). I also built enough extras to include a third Chainaxe or swap out the two Plasma Pistol guys for regular guys with bolt pistols.
* 1x converted Chaos Rhino (for the Berserkers) with Khorne iconography, stock equipment.
* 1x squad of Chaos Marines, unassembled (legs/torsos only). I'm thinking this should be a squad of 8 with
CCWs, a meltagun and a Champion with combi-melta (maybe using the
DV Aspiring Champion model, the clampack one). Likely will need to buy a second Rhino for these guys; alternatively I could assemble a full squad of 10 and give them plasma/autocannon (converted from the heavy bolter on the sprue +
DV heavy stubber; I already assembled one guy with just a bolter as a test fit for something)
* 25-ish assorted Cultits from
DV (about one and a half sprues, I haven't taken a full inventory but I think it's like 12 guys with autoguns, not including the heavy weapons dude or the traitor Commissar with shotgun, and probably about the same number with autopistol/
CCW, again not counting the big dude or the champion, who for those I think is the hooded guy with the axe). Thinking though these are best put to the side for another project since Cultists really don't fit my vision of the warband (they aren't the type to really have what amounts to roadies)
* 2x Helbrutes (one from Dark Vengeance with stock options, one from the box still on sprue that I'm thinking maybe a Lascannon or Autocannon and Powerfist). Not sure of these, I like the models and I like having big stompy things, and fluffwise in my warband it's not so much being condemned as it is similar to how Soul Grinders are made (although they are still every bit as insane)
As you can see, fairly limited. I'm trying to figure out what my next purchase should be; I have about $75 or so to spend right now on getting something extra (could spend more but I have to eat

). I'm not expecting to have a full army, just trying to figure out sort of a "buying guide" so I can pace myself and build things up, since I can't just drop a few hundred buying a lot of stuff, but I don't want to slack too much.
I definitely need a squad of possessed for the Slaughtercult so I think I might have to get that sooner rather than later (also thinking of ways to convert them to be more Khornate since the stock models are
IMHO garbage). I'm just not sure of what order to plan to buy things, or if I should buy like a squad or two of Bloodletters to include as troops alongside my
CSM. I know that an early purchase will be Chaos Hounds (to turn into Flesh Hounds) and Bikers for the Gorepack. I also am kinda wanting to get a few Maulerfiends and Soul Grinders (1 Soul Grinder, 2x Maulerfiends I'm thinking) because as I said above they look awesome. Another option, although a bit pricey, is to get the Start Collecting Khorne box (maybe not immediately?), use the Skull Cannon maybe as a summoning thing, ditch the Bloodcrushers but use a Juggernaut to convert up a Juggerlord, although to be honest I'd prefer a Daemon Prince (fluff reasons) just I feel he'll get blasted too fast. However since the Bloodcrushers aren't that useful and I'm unsure of the Cannon, I think I'd be better off just getting a box of Bloodletters if I want to go that route and build a squad of 8. I get the feeling I'm going to be doing a lot of bitz hunting for this project (I already use Chaos Warrior helmets on my Berserkers and like how they look).
Any suggestions on what I should get or some tips on like how to approach buying them would be helpful, since like I said I need to actually budget out purchases now

I've been trying to come up with like a 1500 point army or something that I'm happy with, but haven't been able to yet.