For application development or create your own app for free ,today people want that how can make them and how we monetize them etc ..etc ...
So for that first open your any browser and search appgeyser.com and your get the screen and click on create now button and then select category for what type of app you want to Create.
Then fill the details of app that app name , description etc. and click on create button and then building of application start and then you get download button to download your app.
If you want to monetize your app then upper side there is monetize option click on that and then select admob and then go to your admob account (admob is like adsence account ) and click on add new app button and then fill details and then get ad unit Id and copy it and paste it in appgeyser monetize option admob.
Then if you have play store account (to open play store account you required 25$) to publish it ..if not have account then publish it on your blog ,website etc..if you don't have that then share it in friend and spread by your own.