Add Watermark is a good app that allows you to add transparent text on a picture. It allows you to put your property text or a logo image into your picture, adjust its size and transparency. You can find it on Google Play Store.
You know if you just get a good editing software on your computer you won't need an app for every little function. Photoshop or Gimp will allow you to put whatever you want on the image and you just reduce the opacity of the layer.