I can't believe that my favorite little Hound Hannah is testing her property line.
Electric Fences are one of the best investments you will ever make if you train your wonderful Hounds properly when you first install the fence. See, I share my life with a Shorthair (a more energetic and curious dog you will not find). She completely understands her property boundries and has never once tried to escape the invisible fence line. She can run freely and play whenever she wants. It's rare that I will even use her invisible fence collar. Once a month I put it on her just so she can hear the sound when approaching the property line.
Now, I'm not sure that you can buy a satisfactory product for under $200. Mine was installed a highly recommended company along with initial training and tips (most important). $200 seems low for a good invisible fence. With 25 acres you need to make sure your transmitter and wire are strong enough to send a strong signal around your property line. Good Luck ilovehounds!