You have tested the example app succesfully on your device before buying the source (aia file)
This is a single user license for you as App Inventor/ Thunkable or any else developer, which means, the
source (aia file) is only for you to use. You are not allowed to pass the source (aia file) to someone else.
BUT you can publish your App on Google Play Store or anywhere else if you want.
ATTENTION: Some sources are marked with "Only for
Thunkable" or "Only for AppInventor". Use only the service for which the source was developed.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.