Having just started in Black Crusade, Im keen to expand my library but have a limited budget (who doesnt)
So, what books are a must and what should I try to get first?
Primarily Ill be playing as a DM

Depends on what you're looking for. Tome of Decay has rules for running a black crusade. Tome of Blood has mass combat rules. Tome of Excess has seduction rules. Tome of Fate has...Probably something. All of them have some new classes and stats for daemons and describe some new worlds. Also I haven't looked at Hand of Corruption but that's useful if you like running adventures out of a book and if Hand of Corruption doesn't suck. I dunno if it does or not.

Tome of Fate has a lot of Psyker related powers for sure (generally, not limited to only Tzeentch).

ToF also has investigation rules - rather weak in my opinion

ToB has legacy weapons.

ToE has expanded minion rules

ToD has possessed character rules.

The legacy weapons are nice so I'd put ToB as the first of the 4 (we're mainly CSM).

Let the sorcerer of the group finance the ToF.

When you get near end game pick up ToD .

Frankly BC doesn't have that many expansions currently, so your best bet is to get the four Tome books as they contain pretty much everything you need and almost everything published for BC.

BYE

...And it doesn't look like we're getting any more expansion books either.

Still glad we got the Tome of Decay after such a long wait.

Still glad we got the Tome of Decay after such a long wait.

Likewise.

...And it doesn't look like we're getting any more expansion books either.

Did they say we weren't?

...And it doesn't look like we're getting any more expansion books either.

Did they say we weren't?

To be fair, they never say anything, but people always assume that the line is over whenever they announce/release a new book.

BYE

...And it doesn't look like we're getting any more expansion books either.

Did they say we weren't?

To be fair, they never say anything, but people always assume that the line is over whenever they announce/release a new book.

BYE

Yes and with good reason, just based on past releases.

Supplements used to popup after 2-4 months, so it's normal that some people might think, after 8-13 months of wait, that there might not be anything more coming.

The next graph shows the release dates, and nothing new has even been announced.

Sure, as long as they don't officially say that the line ended, there is always the possibility that something might happen, and I stress the "might" part. Personally, I'm not seeing anything happening anymore, at least for Black Crusade.

We got a tome for every god, the last tome contained some Chaos Undivided things and I think that concluded things, albeit only the bare essentials. I'd have loved to see a bit more Chaos Undivided, oh well.

But, who knows.

"Hope is the first step on the road to disappointment."