We have taken advice on your behalf and for the beginner the three recommendations seem to be:
1. An African Dwarf Frog (hymenochirus boettgeri) an aquatic frog in the family Pipidae that originates in West Africa. This is considered a good choice as they are a nice looking family of frogs. They are small and active, getting into poses under water then shooting to the surface to inhale, immediately diving again or floating on the surface with legs spread out. These frogs can be kept in a watery aquarium (with a lid on!) like you would a cold water (gold) fish. They spend most of their time under water and you can keep two or three together and they won't fight. Please don't confuse these little frogs with African Clawed Frogs (Xenopus laevis) which grow much larger and are known to eat almost anything that fits into their mouths.
2. If you want a 'frog' out of water then one of the Oriental Firebellied Toads are a good choice as they are easy to feed with crickets and generally care for, are very active and don't hibernate or require heating as they will happily live at room temperature for years.
3. If you want the high life, a good, but not very active tree frog to go for is the very popular and hardy, White's Tree Frog - the smiling frog - (Litoria caerulea) in the family Hylidae. This frog can actually be handled occasionally. White's will require a 'tree' and humidifying. It is liked by many hobbyists. Growing to around 10cm with colouring between blue and brown depending on temperature and humidity. In the wild they have to adapt to seasonal changes of forested areas of northern Australia and surrounding islands. The male may call at night!
