Welcome to Android Central! Are you saying you can't access the Google Play Store? It is likely that the tablet is not certified for Google Play, and therefore not compatible with the store. You may have to rely on other app sources like Amazon Appstore.
One of the reviews on Amazon for this tablet mentions that some of the tablets seem to be compatible with Google Play, and others aren't. You probably have the latter.
Amazon.com: Customer Reviews: Proscan 7-Inch Android Internet Tablet, Capacitive Touch Screen, Android 4.1 Jelly Bean, with Included Case and Keyboard
