That second one actually looks like a great deal.
double wall aluminum rim
saddle with a handle
25.4mm seatpost
split bearing holders
looks like 125mm aluminum cranks
large platform plastic pedals
Looks like a winner when combined with that price.
Edit: about learning to ride
I learnt by going along a wall. Lots of people find somewhere flat with a railing to go along. There is a lot of advice on learning on this site.
check out How to learn unicycling ?