The Clearance Bin

Lego Green Goblin and Minimates Spiderman

Megablocks Batman, Robin, and Batmobile with Minimates Cyclops and Wolverine

Imaginext Superfriends Superman and Batman

Marvel Superhero Squad Phoenix

Marvel Superhero Squad Wolverine and Sentinel

DC Direct Pocket Superheroes: Superman Set

HeroClix Iron Man, Hulk, and Batman

ERTL Batman, Corgi Batmobile.  As for Spiderman: your guess is as good as mine.

Marvel Figure Factory: Blade, Mr. Fantastic, Dr. Doom, Spiderman, and Cyclops

DC Direct Injustice Society PVCs with Flash and Green Lantern

It's hard to get much smaller than Lego figures, so lets start here.  Both Marvel and DC have been represented by this company at one time or another, and who can blame them: everyone loves Legos, after all.

Right now, Batman Legos are hard to miss.  After the success of Star Wars, there's even a video game out.  Sadly, I don't have any Batman Legos to show you: the cost of the sets along with their tendency to NOT go on sale have proven too big an obstacle to overcome.  All I've got is a Green Goblin.
 
To the limited extent that Lego has competition, it usually comes from Mega Blocks, who produced a series of vehicles, play sets, and figures a few years back.  I've got piles of these, since, unlike Legos, these got very cheap at the end of their life cycle.
 
When Lego got the license to take over, Mega Blocks was left without DC sets, which is unfortunate: some of these are actually quite nice.  In particular, the figures were very well made, closer in quality to Minimates than Legos.
 
Did you catch the transition there?  Seamless, I tell you: seamless.
 
Minimates are one of many companies producing figures that are something of a halfway point between Lego men and low-end vinyl.  You can find these for both Marvel and DC, but be aware that while there are some mass market Marvel Minimates (that should provide at least 100% of your daily allowance of alliteration), I've only seen DC Minimates in specialty locations (usually comic stores).  This means you're looking at dropping $8 - $10 for a pack of two glorified Lego men: not exactly a bargain.
 
That said, some of these are pretty cool.  If you're really interested in this sort of thing, Minimates has plenty of competition.  I've seen some exceptional Japanese imports if you're willing to pony up the extra cash (I'm not, which is why you don't see pictures).
 
While we're in this scale, lets take a minute to talk about some other options.  One of my biggest surprises this past Christmas came in the form of DC's Imaginext Superfriends figures.  These are marketed toward preschoolers, with absolutely no attempt I can discern being made to push these at collectors.  And I, for one, can't help but wonder if this is a mistake.  While I certainly understand their appeal to young kids, I think the stylized designs could also have sold to older collectors.  While these aren't my all time favorite figures, they can almost hold their own next to...
 
...Wait for it...
 
Marvel's Superhero Squad.

This scale, clocking in around two inch, represents one of the newest battlegrounds in the collectibles war between Marvel and DC.  While these seem to have initially been directed at young children, Hasbro caught on quickly that they were selling to a different demographic.  Between the exceptional designs, great sculpting, and solid paint work, these really stand out.
 
The real shock, though, is that most of these have some articulation.  This isn't to say they've got ball jointed shoulders or anything, but then they'd probably look silly if they did.  I've said this before, but it deserves repeating: the articulation is limited, but inspired.  Most of these figures have multiple poses they can strike that maintain the integrity of sculpt and balance.

If you're looking for something fun to collect that's three inches or smaller, this is my recommendation.  They're a little more pricey than I might like (expect to pay seven dollars or more for a two pack these days; they were five just a few years ago), but collecting them in moderation won't break the bank.  This is the kind of toy you can collect a pack at a time and put together a nice collection over a few months.
 
I've said a lot about this line in the past and I expect I'll have more to say in the future.  You can find reviews here, here, and here.
 
I should add that DC is jumping into the game, as well.  They've got similar stylized figures on the way.  You can find some pictures here.
 
There are other things in similar styles and in similar scales.  DC Direct has a line of "Pocket Super Heroes" that are fairly cute, though a bit overpriced.
 
On the other end of the spectrum, both Marvel and DC Heroclix are available.  I've got a couple of these floating around: everyone seems to like giving them out at Free Comic Book Day.
 
These are intended more for play than display, of course, but some of the larger ones are pretty cool.  I've never played myself, but I know a lot of people who love it.  Just be aware that you're going to wind up spending a lot trying to build a collection of these guys.

Of course, this is just the tip of the iceberg.  There are easily dozens of different small figures and sets out there for the collector to consider.
 
If you're willing to look on Ebay, you can find die cast figures.  I've got several Batman figures, and they fit in well with my Batmobiles... but that's another article.  I picked mine up used online and from yard sales, so there's some wear and tear.  Even so, I kind of dig these little guys.  I still see them from time to time at stores selling used toys, so keep your eyes open for a deal.
 
Marvel's line of "Figure Factory" sets are also of interest.  I've got a few sets that I picked up on clearance, though these are getting harder and harder to find.  They're nothing spectacular, but I have to say they're pretty cool, especially if you can find them kicking around for a few bucks.  Frankly, I'd rather have these than most of the overpriced PVC sets on the market.

Speaking of overpriced PVC sets... DC Direct produces a ton of them.  Some are actually pretty nice; others are not.  Every now and then you can find some on sale.  Unless you're getting a great price - or are a fan of the format - I suggest you look at other options.  As far as I can tell, PVC sets are more or less a way for companies to charge a premium for something that sidesteps the stigma of being a "toy."
 
I could go on - I've got more junk than this - but things start getting obscure pretty fast.  Then there's the stuff I don't have - such as Battle Dice - that's out there (I haven't seen those cheap enough to buy... and I've seen them pretty cheap).
 
If you're looking at starting a new collection of miniature superhero figures, you really can't do better than Marvel's Superhero Squad (well, you MIGHT be able to, but it'll cost you).
 
This is a competition DC is just getting into, so they might be able to challenge Marvel in this style.  But, honestly, it's going to be an uphill battle.  Hasbro's Superhero Squad figures are going to be tough to top.

But then this is a subject we're just getting started with, as well.  We've looked at miniature figures you can pick up, but things are about to take off.  Next time, we'll glance at the middle range of figures, from three and three quarters to five inches.

And, before you point it out, I'm perfectly aware that those PVC figures fit that range.  I just chose to ignore it, since they fit in better here.

Then, in a few weeks, we'll be getting to the main event: DC Universe Classics Vs. Marvel Legends!