If you're interested in pursuing other app markets, read my TechRepublic post on three reasons to release Android apps into multiple markets.
I reviewed over 40 Android app stores for my book on the Android ad networks, and I keep updating that list. I've seen thresholds as high as $250, which is a bad deal for smaller developers. The catch is some markets have payout thresholds, which means you won't see any income until you sell a certain amount. Many other app markets pay about 30 days after the end of the month. Google Play is the best when it comes to payouts it pays you out just a few days after the month is over, and with apparently no minimum. Almost every Android app market holds on to your money for a period of time. Unfortunately, you don't get your money immediately when you make a sale. I think that paying the distribution channel 30% for their hard work to build the marketplace and bring in the customers is money well spent and significantly better than the deal you would get selling physical goods.
So can you do about this? For the most part, take your lumps and move on. While it's good to engage those app stores, you can't ignore big markets like Google Play. Most of the app stores that pay more than 70% of the revenue to developers don't have very high traffic. It's not just about getting the most from each sale - it's about getting lots of sales too. There are app stores that differentiate themselves by paying a higher percentage to the developer for example, I've seen developers get as high as 91% of the app's sale price from SlideME. We can probably thank Apple for setting that as the standard - they weren't the first, but the iOS app ecosystem has been used as a model by many other players in the mobile app space. The industry standard for how much income app stores take is 30%.