It would have been good if you would have written some more description of your problem.
You didn't mention why Team Viewer is not an option for you. And why you *only* want Ammy Admin?
You didn't mention what is the exact problem you face after 1-2 min of usage? Does it ask to buy?
You can't decide to "not to look for alternative" and also not to buy the product if its not share/free ware.