DV is the unqoustinable best path for chaos starters, if you don't mind some dirty work.
You see, with some work and some bits you can convert nearly everything to chaos with ease, so your army gets:
HQs
SUPER fancy chaos lord (kanon)
Sorcerer (librarian, can be used as sword team leader as well)
Team leaders: (switch around to use the one you need each list)
Champ with axe
Champ with axe and combi-melta
Champ with mace
Champ with Pfist
Champ with claws
Champ with nothing special (the
DA sarge, can be used as regular dude too)
Fancy sword dude (
DA captain)
Troopers:
7 bolter marines
2 fancy bolter marines
Plasma marine
Heavy weapon marine (requires conversion from the plasma cannon, that's the hard model to convert.)
Cult:
9
CCW cultists (one of is the assault team leader)
8 gun cultists
Flamer cultist
HStubber cultist
Cultist leader with shotgun
Bikes:
Champ biker
Plasma biker
Regular biker
Terminators: (can be used to create terminator lords too)
Termi champ (the sword dude)
2 PFist termies (might want to swap out to power weapon off bits if you got some, shouldn't be too hard to get spare left-handed power weapons off people)
Ofist+autocannon termi (the assault cannon is close enough, again the fist should probably go.)
CF termi (again, you wonna get bits to switch hand)
And the Helbrute.
If that aint a steal for its price, I don't know what is. even if its not the most top-tier units
CSM has, they are no real useless dudes there.
You can make over 1000 points worth of a crimson slaughter army (for the relics) just by taking models as they are, with no marks, and with models to spare (you will use only one or two of the "team leaders" after all) and it will even be a decent, well-balance casual army.
With some conversion works (mainly guns) and good mark choices, you can even make it into a good army in general (not top tier turny army, but a good army)
After all you can keep modifying some dude as long you got weapon bits to get more special guns around. and can make really nifty stuff (like turning two termies into oblits, probably the autocannon and chainfist)
Ironically, its the
DA who does not get a good deal here, they get a better model list on paper, but anything they got can be chaosified, but the chaos dudes cant be loylaised, and the
DA side can't even make a proper legal basic army with it with no way to make a second troop choice. (and
DA are overpriced point-wise in general.)
Not good for splitting, but good enough if you just want to get chaos
If your friend just wants to "get an army" and does not really care what army, there are better starting paths out there than
DV for
DA. if he wants
DA spesifically, well-
DV is the best he's got.
Other worthy starter deals of various armies:
Wrath of the Hive Mind
Tau battleforce (just add
HQ and play
FE so crisis suit teams are troops)
Warriors of the Fang (good set of
SW units)
Adeptus Astartes Strikeforce (requires to make two 5-man
TAC squads)
Space Marine Strikeforce (NOT the same as what's above. pretty good set. currently sold out, not sure if returning?)
Necron battleforce (just add
HQ. barge recommended as it can be tank+
HQ in one kit.)
Eldar battleforce (again, just
HQ needed)
Shardstorm (not the greatest unit picks, but its a stand-alone army)
Cadina/catachan defense force (technically stand alone army, or a huge troop choice and a tank-depends how you deploy it.)