Is there anyway to turn on tablet if the power button fell off??

SOURCE: on button fell inside tablet.

I don't know what to do about Walmart, but perhaps you can fix, or work around the problem yourself. Tablets come apart easily, but you need to be careful. Take a very thin blade knife and gently pry around the edge of the screen. Work it up evenly, all the way around. With the screen off (it plugs into the main board), you should be able to locate the defective switch, in order to see if it is fixable. Perhaps it is broken, but you may be able to use a toothpick, or other object to activate the switch, after you take out the loose pieces, and reassemble the tablet. I doubt there is any way, short of a miracle, or someone very creative, to fix or find a replacement for the switch. Your next alternative is a new tablet. I hope this is helpful. Let me know if it is... or ask more questions. Thanks.