Version 0.11 adds the first in-app-purchase to Tic-toe-collection: Prime. This is basically just an option to play without ads. It will disable the banner ads in game as well as the interstitials that appear when you exit a game. It also lets you skip levels freely in campaign (and thus, eliminates the rewarded ads that you might otherwise see).
The current price is £1.19, $1.49, €1.39 or whatever the equivalent is in your local currency. Exactly how it is these prices is interesting. In general, I don’t support the idea of ending prices in a 9 (I try to avoid psychological trickery), so I chose the price to be a nice round £1. Google adds sales tax on to this, which in the UK is VAT at 20%. So the price should be £1.20. Sadly, I was defeated by Google. Once the local price is determined, it is then adjusted using “locally relevant pricing patterns”, which in many cases makes the price end in a 9. I could manually edit the price for any currency I think, but there are a lot of them, and as the exchanges rates fluctuate, I think I would have to update them.