Selling on the slider

I was an economics major in college, and one of the things you do as an econ major is draw a lot of graphs, many of which purport to show the supply and demand for a particular good. You’re always looking for the point at which the curves cross. That point tells you, among other things, the price for that good.

The price.

I drew so many of these dumb graphs, and yet I never noticed the deep assumption built into the exercise: That of course you must choose a single price for a good.

So you can print it in the catalog.

So you can write it on the tags.

I learned all of this around the turn of the century, and prices have gotten a lot more interesting in the years since, thanks to the internet and, more specifically, to the fact that so many prices are now shown on screens rather than printed on paper. Today, the notion of the price is breaking down, being replaced by something more flexible.

Some of the forces behind that change are of course quite cold and rational, powered by new algorithms. But more of them are humane — the kind of forces we never learned about in econ 101 — and powered by a new interface.

Well. Not even that new.


The slider is a hot piece of technology that will play a central role in the future of prices.

The slider need not be cold, and it need not be rational.

It’s not economic efficiency that moves the slider, but emotion.

And for my money, this is the most interesting checkout screen on the whole internet.

That’s what you see when you’re about to buy a Humble Bundle. There’s a lot going on there, so let me just break it down quickly. The Humble Bundle is a popular product with roots in indie video games that’s expanded into music, movies, books, and more. The deal goes like this:

  1. You, the potential customer, are presented with a bundle of merchandise. Maybe it’s a dozen video games; maybe a truckload of digital comics.
  2. You decide what price you’d like to pay for all of it together. It can be as little as one penny! (This is section 1 in the screenshot above.)
  3. You also decide how that price should be apportioned, splitting it between the content makers, a set of related charities, and the company Humble Bundle, Inc. (This is section 2 above.)

There are some nuances. Most bundles include extra content that you only receive if you meet a certain minimum payment — $10, perhaps. More interestingly, bundles almost always offer extra content that you receive only if you exceed the current average payment — an incentive that, of course, has the effect of slowly raising that average over time.

Honestly, it feels less like a checkout screen and more like a video game.

Humble Bundle’s sliders are the most elaborate you’ll find anywhere, but the basic element is all over the place. The indie video distributor VHX has a nice one:

And while the sell-anything site Gumroad lacks a draggable slider…

…it delivers a clear message: There is no the price.

(Kickstarter offers the same ability to pay extra, but it’s often lost in the complexity of the project rewards. I think Kickstarter projects tend to feel more like small catalogs — listing many fixed prices — than sliding scales.)

The slider is a natural fit when you’re buying something from a specific individual, possibly someone known to you or whose work you’ve long admired. It acts as an affinity-meter through which you can convert surplus units of love and gratitude into cold, hard dollars.

But there’s more to the slider, particularly in Humble Bundle’s implementation. It has to do with communication.

The information content of most payments is one bit: either you agree to the asking price and make the purchase, or you don’t. When a payment goes through a slider, that information content increases. When it goes through an interface like Humble Bundle’s… well, I mean, look at this!

A payment can bloom into a rich little packet of information, much better than a survey because it’s weighted with dollars.

(It’s quite possible you feel exhausted just looking at Humble Bundle’s bank of sliders. In practice, they’re easy to manipulate and surprisingly fun to fiddle with. It’s really worth playing around with them for a moment.)

The slider is not appropriate in all, or even most, situations. It would, for example, be an affront to see one on Apple’s checkout screen. “Oh, really, hugely profitable megacorporation? I can elect to give you more money? Thanks.” Most products’ prices will stay fixed — catalogs and tags.

But the slider still has gains to make. There are a lot of products out there that would benefit from a more flexible, more emotional form of payment. Maybe most products created and sold by individuals should be sold on the slider. Maybe most writing should be! We don’t know yet.

That’s exciting. It means we’re still learning new things about prices and markets, and about people, too.

We’re learning that a price can be a bundle of information richer and more useful than simply “deal or no deal.”

We’re learning that it was perhaps never quite right to price indie movies the way we priced refrigerators.

Soon, we might have to start revising those economics textbooks.