As part of our weekly Monetization column, we spend a lot of time looking at the economics of free-to-play games.

Part of this has me, calculator in hand, working out the conversion ratios between real money and in-game virtual currencies.

And I've noticed something significant in terms of pricing philosophy.

How much is that virtual doggy?

It came to light when I was considering Gameloft's Total Conquest.

This is basically a clone of Supercell's Clash of Clans so I wasn't surprised to see that as well as the gameplay, Gameloft had also used the same basic currency bands as Supercell's game.

Clash of Clans' economy for its Gems hard currency

Clash of Clans has five bands for its in-game hard currency - Gems - which range from $4.99 for 500 gems, up to $99.99 for 14,000 gems.

Total Conquest's economy for its hard currency - Tokens (2 screenshots combined for clarity)

Total Conquest has six bands for Tokens, but excluding the lowest price point $1.99 (which Clash of Clans doesn't have), the others match exactly.

This got me interested, and looking back at previous Monetizers.

That's a match

And what did I find? Gameloft isn't the only company following Supercell's lead.

GREE is following a similar path. The Gems hard currency in its recent release Dragon Realms follows Clash of Clans with five bands at exactly the same real money amounts and virtually the same conversion rates. It's also the same story with GREE's earlier War of Nations.

The Gems hard currency in GREE's Dragon Realms also follows the Clash of Clans pricing pattern

Chair Entertainment's Infinity Blade III takes a similar approach too, with its Chips hard currency using five bands ranging from $4.99 to $99.99.

The price is right

I think there are two psychological elements to this choice of currency breakdown.

Certainly using real money amounts of $4.99, $9.99, $19.99, $49.99 and $9.99 is fairly standard across F2P games.

Very few titles use $39.99, $29.99 or $14.99.

But what's significant about the pattern is that $1.99 is matched with around 100 units of in-game currency; $4.99 equals 500-550 units; $9.99 = 1100-1200 units; $19.99 = 2400-2500 units; $49.99 = 6000-6500 units; and $99.99 = 14,000-15,000 units.

In all cases, this means gamers get around 100 units of hard currency per $1 spent, rising to around 150 per $1 if they spend $99.99.

This feels correct.

In comparison, Supercell's Hay Day gives you 3,750 Diamonds if you spend $99.99 while EA's Plants vs Zombies 2 gives you 450,000 Coins if you spend $99.99.

Low-end transactions in EA's Plants vs Zombies 2

In both these cases, the conversion to 37.5 units and 4,500 units of hard currency per $1 spent seems, respectively, too low and too high.

Follow my leader

Of course, this isn't to say that games that follow this system will be successful. Hay Day doesn't follow it and is very successful.

Equally it's hard to tell if Supercell came up with this pattern. I suppose it could have been GREE.

Out of interest, GREE's Japanese rival DeNA takes a similar approach with six bands ranging from 100 units for $0.99; 505 units for $4.99; 1020 for $9.99; 3100 for $29.99; 5210 for $49.99; and 10,524 for $99.99 [this is in the case of The Drowning and Blood Brothers].

The rather abstract in-game store from DeNA's The Drowning

It's pretty close in terms of the general pattern, although has weird in-game currency amounts - 10,524? - plus that odd $29.99 price point.

The really interesting conclusion to ponder, however, is are gamers now used to receiving around 100 in-game currency units per dollar spent?

If so, the quicker developers start using this convention, the better.