I downloaded some games for my nephews. Some were free, but some of the better ones, I paid for. Don't get anything too good if you want your phone back.

if you use I-tunes, you can search free game apps and they list them by most popular downloads. Here's some I downloaded about a year or so ago. I'm sure they have new ones by now.
Free:
Sheep - by Kronos- simple, but we laugh our pants off. You have to keep the sheep up in the air and blow him up with air to that while he collects coins. Silly, fun and quick gaming.
Worder- very good- you have to take the letters given and come up with all the words that you can possibly make from them. Funn for adults too. MANgo and I play it on the airplane.
FDG- Parachute Panic- Hysterical- you have to keep the parachuters from landing in the water or they get eaten by sharks. Stick figures.
Can't remember the costs or if free or not:
Air Hockey
Tap Tap- I think free- but stupid if you ask me
Enigmo- excellent puzzle game with water droplets- really gets you thinking.
Sol free- free solitare game I think
Games with great graphics, but definitely cost money ( can't remember how much- they also go on sale a lot too)
Enigmo
Crash Car Bandicoot
Frogger
Nanosaur 2
Parking Lot- this was inexpensive- may have been free- but it's a great puzzle- you have to figure out how to get the car out of the parking lot.
Waterslide- funn
and I have that bowling game and fishing game that GTTBM has- both funn for kids. I have Flick bowling. Graphics are good and you can play solo or against someone else.