Editing Age of Darkness-Warhammer 30k/2.0 Tactics/General Tactics (section)

===But I like my kidneys!===
Then you shouldn't be playing Warhammer. 

But on a more serious note, a lot the Heresy stuff is still resin and sold on FW making it a more expensive game system to play than 40k (only marginally but still). Luckily a lot new plastic kits have been released specifically for 30k (with more on the way) and there are a lot of conversions and units you can make from the cheaper GW plastic lines, so if you have grown fond of your organs and starting a drug empire seems like too much hassle there are "cheaper" alternatives you can use from GW. There is also 3d-printing and bootleg copies, but don't try bringing those in GW stores.

*Stuff you can use in 30k:
**Those plastic space marine kits made specifically for Heresy (duh).  As an added benefit these won't be at risk of going out of stock anytime soon.
***You could also use the 40k Tactical Marine Squad, albeit not out of the box. Hear me out: if you're willing to put the work in, shaving off the chest eagles, clipping the helmet crests until the helmet is flush, filing the knee pads to a point and adding either some sculpted cables or some guitar strings to make a suit of MKV plate is among the easier conversions out there.
***Note the above requires a LOT of converting and really should only be done if you like converting or have spare 40k Tacticals laying around, given a 40k Tactical Squad of 10 marines costs US$55 ($5.50 per marine) compared to a 30k Tactical Squad of 20 costing US$80 ($4 per marine).
**The plastic Custodes and Sisters of Silence made for Heresy (double duh).
**Mars pattern vehicles (this would be the GW Rhinos and the vanilla Land Raiders, though Mars pattern is smaller than newly-made Deimos, so it can cause trouble in hyper-competitive environment). 
**Castraferrum Dreadnoughts.
**Any GW Space Marine in Mark II-VI armours.
**Imperial Guard models.
**The less goofy plastic Mechanicus models (like all the Techpriest models).
**Pretty much any human model with the Purity seals/Inquisitorial/post Heresy symbols shaved off. Even Converted Warhammer Fantasy models can work for Militia.
**Plastic Knights. They have rules for 30k and have their own army list.
**Converted Chaos models. While Chaos Space Marines wear an unholy mix of mk VI and VII, thanks to an idiot who sculpted Word Bearer Praetor it's now a Heresy accurate armour mark, and with some work can be used for late Heresy Word Bearers, Sons of Horus, and Black Shields. Possessed can also be used for Gal Vorbak. Daemon engines can be used by Traitor Mechanicum (not Defilers though, those were made after the Heresy) in conversions and Daemons of the Ruinstorm are literally just Daemons, and the whole army based around converting your own force (more specific details about their conversion opportunities are on their tactics page).
And on the flip side a lot of 30k stuff is usable with 40k and by extension kill team.