I have enjoyed my steaks at El Gaucho.
The price varies for what you order. My steak was $29,50.
They do have a lunch special for $20 dollar. That's what my girlfriend and I did during lunch last time. You get a 3 course meal, and it's really good.
The food is great, the service is good but it took a while to get our food. Still my favorite steak restaurant on the island.
Here's their menu:
http://www.elgaucho-aruba.com/menu/index.html