Is the "Tetra 5.5 gallon kit" or the "Water Wonders 3 gallon" suitable for betta fish?

The Water Wonders 3 has an adjustable filter for bettas, but from what I hear, one needs at least 5 gallons to properly keep them. So, there is a 5 gallon kit that is actually cheaper, with a power filter. Are powerfilters OK too?