You can try with OpenDataKit (ODK) or KoBo Toolbox, which is developed from the ODK platform and seems to be a little more user friendly. They are both free, and will require some learning, but in general they are quite good. We used KoBo for developing a dumpsite assessment app and we are quite happy with it.
Just bear in mind that, in case you are collecting sensitive data (e.g. date of births, medical information, politically sensitive stuff) you will need to spend a little in data security to prevent access to/theft of your data. Please be safe and remember: passwords are like underwear, you need to change them often or you’ll cause a stink 😀
There is an excellent free app that you may want to have a look at, called mWater. go to portal.mwater.co to design surveys and manage data, and go to Google play and download mwater app (or via web on app.mwater.co). It is geared towards monitoring WASH programs and very versatile to collect, analyse and map M&E data. It is not a full project management system – but you may find it suitable for your needs – as it is very user friendly. We use it for our sustainability surveys and now water point mapping, and exploring further options.