Just to clarify further, I did a bit of digging. The 40k boxed set “Assault on Black Reach” is regarded as being by far the best value of the starter sets GW have done for some time. It’s $90 and contains ~400 points of Orks and ~600 points of Space Marines. The SM army also isn’t a “valid” one according to my hasty googling.
Alternatively, the SM army battleforce is also $90 and is 500 points of Marines, but is a more balanced force I think. Certainly if you added it to the AoBR set it would be a good start. The trouble is it wouldn’t be anywhere near enough still.
In the UK a normal game of 40k is 1500-1750 points, in the US it seems they prefer larger games of 2000pts+. Realistically you can eke maybe 1200 points out of the two sets.
WM/H games have certain points values for games - 15, 25, 35, 50, 75, 100, etc. The most common by far is 35, but they all get played and the lower points value games are recognised as a fun, quicker way to still get a good WM/H experience.
The WM/H battle boxes aren’t exactly 15 points but they’re usually 11-14 and they’re all pretty much balanced against each other. For $50 you get a warcaster/warlock and 2-3 jacks or beasts. To get that up to the most common points value (again, not required but we’ll go with it for the basis of comparison) differs for each army but let’s take everyone’s favourite “good” guys, Cygnar:
Boxed set
Caster: Stryker
Ironclad heavy jack
Lancer light jack
Charger light jack
Which is 11 points on its own. A random addition of crap I’ve never used to make it 35 points:
Squire ($10)
Black 13th Character unit ($17)
Long Gunners ($28)
Stormblades w/Officer+Standard ($43 + $20, ouch!)
Swordknights ($40)
The bigger chunkier infantry units are expensive if you ask me. Anyway, that fairly random selection tots up to $160 ish. That makes it $210 for a full 35-point army, compared to the $180 for part of a Space Marine army. Is it enough to be a point in WM/H’s favour? I have to say I think so, purely because of how easy it is to swap out the casters for a different experience, and because of how well the game works at 25 or 15 points.
It’s still not a cheap hobby, though. I reiterate my recommendation for Epic 40k as an awesome tabletop game that can be picked up on the cheap :D
Edit: Another major plus point for Epic is how most of the units are very simple to assemble and paint. WM/H are still some way behind GW games in terms of ease of assembly and sheer quality, though they’re improving. 40k and fantasy have some awesome models and the quality of the design is top notch.